Tripadvisor.com is a good place to start 

And LonelyPlanet.com

The Stone Forest is a decent day trip, about an hour train ride from Kunming. Karst rock formations. People will try to sell you tickets to a "secret" side exit... It's a scam, go to the official gate.
Dali, Lijiang, Tiger Leaping Gorge are all weekend trips to make from Kunming.

Within Kunming there is Green Lake Park, a beautiful former Ming royal retreat.
Various nice (and old) Temples...If you're into history, the hotel where the Flying Tigers (A group of American fighter pilots that helped the Chinese Airforce run missions againsy the Japanese until the Japanese attack on Pearl Harbor) has been converted to a themed restaurant.
Yunnan is host to a good portion of the minorities in china, so the food selection js very diverse, but expect spicy food...
Most of the hotels that are 'rated' for foreigners run on the expensive side. 'the hump' is probably one of the least expensive places there that ive found that can rent to foreigners, but its a hostel.
Hopefully your Chibese is pretty good, because you will be hard -pressed to find English speakers there. Also, the local dialect is very difficult to understand.
Tripadvisor is pretty good, thelonelyplanet is terrible for kunming. also, Frommer's is ok, but is off for times and prices for most of the places.

Thx Guys  

Stay away from the train station, did you hear about all the people that were murdered and injured there???