If you're focused on one area, and if you want to know about properties before they are marketed via the MLS, one of the best ways to find out about such notices of default and trustee sales is to check the city/county records because this info will be made public. There are notices for trustee sales where prospective buyers can bid on different properties.
As of this writing, there are 13 homes that are REO (bank owned) in San Ramon. 4 are condos, 6 are detached single family homes, 3 are townhouses. Lowest price is $218,900 for a condo, and highest price is $1,899,000 for a detached single family homes. Check them out: http://maxebrdi.fnismls.com/publink/default.asp?GUID=f27b4f8
If you're looking at short sales, there are 56 offered at this time.
Lenders will always use realtors to market these properties if no one buys it at auction because this is the surest way to get the property on the MLS for the widest distribution. If you have a realtor working for you, that realtor may be able to send you an automated email notification whenever such properties hit the market. A realtor can also guide you through the maze of writing an offer on foreclosed homes. It's not for the faint of heart. We realtors can help.