I buy foreclosures/preforeclosures and rehab them for a living. It's very much a YMMV situation. There are houses that I thought no one would be interested in that "everyone" seemed to want, and houses that I thought "everyone" would want that no one bid on. So, you just never know.
First big piece of advise I can give you is to learn your state's foreclosure laws (process, length of time owner has to redeem his house, etc). Every state is different. Then learn the procedures for your county (where information is posted, etc).
Second advise is not to get attached to any one particular house. There are lots of them out there, and many more coming with adjustable interest rates rising.
The Register of Deeds has information that may be helpful. If you are serious about a house, you definitely want to pay and attorney/paralegal to do a title search, so you know what's "out there". Are you bidding on a foreclosing first or second mortgage, etc?
NCRedding is right about homeowners doing some damage. I looked at a 6500 SF upper-end house not too long ago. The homeowner had completely demolished the inside: sledgehammer to the walls, black paint on the carpet, cement down the toilets.... On the other hand, some houses are in mint condition. Just do the best possible research you can.
I wouldn't waste time with RealtyTrac. Their information is too outdated. Ocwen would be a good site for bank-owned houses. Lisa, PM me with where you are. Some areas have great pre-foreclosure info; some not so good; some non-existent.
Good luck! This can be addictive.