yepp craigslist is the best...

you can also check out housingmaps.com for some cities.

Condo is an apartment in a big building. The difference between condo and apartment is in the ownership and stuff (no big deal)

a townhouse is a home that is attached to adjacent houses

a house is simply a house...

you will need to sign a one year "lease" (contract) and if you need to be out of town you can sublease (bring somebody in for a temporary term)

Gas is currently really expensive in the US so finding a place with electrical heating is much better. otherwise you might need to buy an electric heater if you don't wanna see a $500 gas bill in winter time.

typical prices for utilities (which are shared between roommates are

Gas: $30 in summer...at least $100 in winter
Electricity: $50 in winter...100 in summer
Cable TV: $50
Cable internet: $40
Water: $40

these are approximate...