Almost all of these homes in our area are listed in the MLS system. However, you can also go to Fannie Mae's site at http://reosearch.fanniemae.com/reosearch/
However, what you'll find is that it is currently listed in the New Jersey MLS. There's also HUD's site - http://www.hud.gov/homes/homesforsale.cfm
Here too you will find most if not all of the properties already listed in the MLS system.
Bank foreclosures are normally handled by real estate brokers who are their brokers of choice as such companies exclusively service the foreclosure market and are basically a conduit to the MLS for the banks.
The best answer sure sounds self serving because it's best to find a real estate agent who is a full time professional and understands both the foreclosure and short sale market. With short sales, a broker needs to do a search through the NJMLS inventory for you and then needs to be knowledgeable enough to deal with these properties for you.
I hope that this answers your questions; if it doesn't just let me know. Oh and one more thing - never, ever pay for a list of foreclosures as this is almost always not worth even one penny.