Getting to view REO's before they are listed is easy.
The company I work for has what we call a pre-list of REO's. It's a list of properties we are contracted to list for any one of the 18 banks we work with, that we are in the process of cleaning, re-keying and doing BPO's.
I have several investors that I have given this too and have made several offers before the property is listed. The problem is we have no idea of the number the bank is actually going to list the property at, when the property is going to get listed (2 days, 2 months...) and they almost NEVER entertain an offer before the property is listed. You can spend a lot of time spinning your wheels with a pre-list and end up with nothing more than frustration.
My best suggestion is to get a broker who knows what they are doing. A broker that can weed through all the new REO listings and send you the ones that are the deals. Then get a system together that allows you to react quickly to new listings.
Reacting quickly means getting the property from the broker, reviewing property for a construction budget, work with the broker to come up with an ARV (after repair value) and make an offer. All with-in 24 hours of the property being listed.
If you can't do this your going to have a tuff time competing for the deals as there are several others that can.