So I posted this yesterday in someone else's thread about banana's being safe, seems that everyone found it useful so I though I would give it it's own thread so everyone can see it...plus it took me forever to type up 
I didn't make this, I copied it from a dog book so I can't say 100% that every thing is right but it seems like a good guide line....
Fruits:
IMPORTANT: Remove all pits and seeds from fruit, almost all of them are poisonous to dogs.
Apples: Vitamin C and pectin. Leave the peel on, just be certain to remove all the seeds
Bananas: High in potassium and magnesium. Soothing to a dogs gastrointestinal tract.
Berries: High in vitamins A, C, potassium and fiber
Lemons, Limes, Grapefruits, Oranges and Tangerines: High in Vitamin C and the white under the peelings contain bioflavonoids, which is essential to vitamin C absorption. Caution: Citrus peels are poisonous
Melons: High in vitamin A, C and potassium.
Peaches, Apricots, and Nectarines: High in vitamin C, A and contain calcium.
Raisins: High in vitamins A, B complex, potassium phosphorous, magnesium, iron, calicum and fiber. Feed in small amounts only.
Grapes: Feed occasionally and in small amounts only. Recently found that large amounts of grapes can cause kidney faliure.
Avocado: Rich in vitamin E and some protein. High in fat, good for skin, coat and weight gain.
Vegtables
Asparagus: High in carotene, selenium and vitamin C.
Beans: High in protein, fiber, potassium, iron and thiamin. Too much can cause intestinal gas or discomfort.
Beets: High in copper, manganese and potassium. Temporarily changes color or urine and feces.
Broccoli: High in calcium, potassium and fiber.
Brussel Sprouts: High in protein, vitamins A and C, riboflavin, iron, potassium and fiber
Cabbage: High in vitamins B5, B6, C and E
Carrots: High in fiber, beta-carotene, potassium and vitamin C. Personally a favorite treat by my teething pup!
Cauliflower: High in fiber, vitamin C, potassium and zinc
Celery: High in chlorophyll. Many dogs do not like celery because of the strings, even when cut up in bite size pieces these strings can cause throat irritations.
Corn: High in fiber and good amounts of iron, zinc and potassium. Corn must be processed for proper digestion. Never feed you dog corn on the cob, as the cobs can cause obstructions in the intestines.
Greens: High in vitamin A, C and fiber. Always a good idea.
Kohlrabi: One of the higest vegetables in potassium and vitamin C. Both the greens and bulbs must be processed before eating.
Lentils: High in protein, iron, thiamin, riboflavin and niacin; the sprouts are rich in vitamin C. Only feed cooked.
Okra: High in fiber, carotene, vitaman B complex and C.
Parsnips: High in fiber. feed occasionally.
Peas: High in fiber and magnesium.
Pumpkin: High in fiber, vitamins A, B, calicum, copper, magnesium, potassium and zinc.
Squash: High in nutrients.
Sweet Potatoes: High in vitamin A.
Turnips and Rutabagas: High in fiber and nutritous.
Potatoes,Eggplants, Onions, Radishes and Spicy Peppers: Do NOT feed!
Lettuce: Has very little nutrition and too much can give your dog loose stools.
Tomatoes, Cucumbers, Peppers and Spinach: These vegetables are enjoyed by most dogs but should be used only on occation. Too many of these goodies can cause your dog gas, bloating and/or intestinal upset.
Garlic: Loved by most dogs. It is good for the health of the intestinal tract and immune system. Only give raw garlic in small amounts.
I didn't make this, I copied it from a dog book so I can't say 100% that every thing is right but it seems like a good guide line....
Fruits:
IMPORTANT: Remove all pits and seeds from fruit, almost all of them are poisonous to dogs.
Apples: Vitamin C and pectin. Leave the peel on, just be certain to remove all the seeds
Bananas: High in potassium and magnesium. Soothing to a dogs gastrointestinal tract.
Berries: High in vitamins A, C, potassium and fiber
Lemons, Limes, Grapefruits, Oranges and Tangerines: High in Vitamin C and the white under the peelings contain bioflavonoids, which is essential to vitamin C absorption. Caution: Citrus peels are poisonous
Melons: High in vitamin A, C and potassium.
Peaches, Apricots, and Nectarines: High in vitamin C, A and contain calcium.
Raisins: High in vitamins A, B complex, potassium phosphorous, magnesium, iron, calicum and fiber. Feed in small amounts only.
Grapes: Feed occasionally and in small amounts only. Recently found that large amounts of grapes can cause kidney faliure.
Avocado: Rich in vitamin E and some protein. High in fat, good for skin, coat and weight gain.
Vegtables
Asparagus: High in carotene, selenium and vitamin C.
Beans: High in protein, fiber, potassium, iron and thiamin. Too much can cause intestinal gas or discomfort.
Beets: High in copper, manganese and potassium. Temporarily changes color or urine and feces.
Broccoli: High in calcium, potassium and fiber.
Brussel Sprouts: High in protein, vitamins A and C, riboflavin, iron, potassium and fiber
Cabbage: High in vitamins B5, B6, C and E
Carrots: High in fiber, beta-carotene, potassium and vitamin C. Personally a favorite treat by my teething pup!
Cauliflower: High in fiber, vitamin C, potassium and zinc
Celery: High in chlorophyll. Many dogs do not like celery because of the strings, even when cut up in bite size pieces these strings can cause throat irritations.
Corn: High in fiber and good amounts of iron, zinc and potassium. Corn must be processed for proper digestion. Never feed you dog corn on the cob, as the cobs can cause obstructions in the intestines.
Greens: High in vitamin A, C and fiber. Always a good idea.
Kohlrabi: One of the higest vegetables in potassium and vitamin C. Both the greens and bulbs must be processed before eating.
Lentils: High in protein, iron, thiamin, riboflavin and niacin; the sprouts are rich in vitamin C. Only feed cooked.
Okra: High in fiber, carotene, vitaman B complex and C.
Parsnips: High in fiber. feed occasionally.
Peas: High in fiber and magnesium.
Pumpkin: High in fiber, vitamins A, B, calicum, copper, magnesium, potassium and zinc.
Squash: High in nutrients.
Sweet Potatoes: High in vitamin A.
Turnips and Rutabagas: High in fiber and nutritous.
Potatoes,Eggplants, Onions, Radishes and Spicy Peppers: Do NOT feed!
Lettuce: Has very little nutrition and too much can give your dog loose stools.
Tomatoes, Cucumbers, Peppers and Spinach: These vegetables are enjoyed by most dogs but should be used only on occation. Too many of these goodies can cause your dog gas, bloating and/or intestinal upset.
Garlic: Loved by most dogs. It is good for the health of the intestinal tract and immune system. Only give raw garlic in small amounts.