I get a lot of questions about where to find REO properties (Real Estate Owned) being in this profession and so far this is my best answer: If you are serious I can recommend a local Realtor otherwise if you are just curious try YahooRealEstate. Here you can search out NOD's (Notice of Default) and foreclosures but when you want more info, such as an address, you will have to pay for it.
I'm cheap so when I come across free I take note : )Oregon Dept of Veteran Affairs
VA Properties (and more)
USDA Rural Properties
Fannie Mae HomePath Properties
Freddie Mac HomeSteps Properties
IRS Seized Real and Personal Property
US Marshall's Office Seized Real and Personal Property
As I come across any additional links (feel free to enlighten me) I will most certainly post them here.