I would start here:
1) Read the laws of your state concerning foreclosure.
2) Hit the Search button at MSF and search for cases in your state, read and determine the current status of this issue in your state (for example in Michigan the status is currently very anti Mers)
3) Read your mortgage, find the paragraph that sets forth the way the lender is suppose to proceed in a default situation. ( Par 22 in standard mortgages). Determine whether those procedures were followed by the lender/servicer/foreclosing attorney.
4) Go to your county and get all of the documents that have been recorded in reguards to your property ie mortgage, assignment etc.
This will give you a very basic understanding of your situation... Enough information that you can carry on a conversation with an attorney in a free consultation...
Read as much as you can on this forum, get educated... And Make sure your attorney knows more about this portion of law and the current status of cases in your jurisdiction then you do..