If you owe back taxes then you may want to pay attention to this. The OIC (Offer In Compromise) Program was designed to allow delinquent taxpayers to negotiate a lump-sum payment. Up until recently most offers to the IRS were denied. Taxpayers who had homes that had appreciated in value were told to get a second mortgage to pay the bill. Well, that has changed since things went "kaplooey" in the housing market during this recession.
The IRS is starting to consider all reasonable OIC's because of the bad economy. The IRS is now reviewing each OIC on it's own merits. If you have a lump sum to make a one time deal with the IRS it may be worth the gamble. You could end up paying dimes on the dollar.
There is a $150 application fee when you apply to do an OIC. But you can save thousands in the process based on your own circumstances and back taxes. For more info go to IRS.gov and do the keyword search "Offers in Compromise".