First..The Banks/Gov maintain Databases of the properties for sale REO/Foreclosures for the public to use.
Besides providing the property information the purchase/bid process is explained. Sites like these.....
http://www.mcbreo.com/ .... http://bankofamerica.reo.com/search/
You can find the links to these sites and more here.....http://www.biggerpockets.com/bank-reo.html
For Tax sales and other sources check these out.....
Just because something is on Realty Trac doesn't mean it is actually for sale, nor can they offer the marketing information you'll need to know - what's it like? are their pics available of the inside? how much land? what do they want for it?
Call a REALTOR today.