I have no idea what the present value of my home is. Do I need to pay to get an appraisel to determine this for me?
An experienced appraiser will give you the best estimate, otherwise you could try Zillow.com
To really know how much value has been lost, sell the house just before the crisis, then sell it again now. The difference is how much it has devalued.
Save some money & survey via papers & neighbors your local market local agents could help if approach properly.