On January 20, 2012, the IRS made two significant changes to its streamlined installment agreement program. First, the dollar threshold increased from $25,000 to $50,000. Second, the timeframe to pay changed from 60 months to 72 months. Basically, any taxpayer with a liability (after principal, penalties, and interest) below $50,000 is eligible for a streamlined payment plan that will allow them the ability to pay off the liability evenly over 72 months.
Robert McKenzie, a tax attorney based out of Chicago, wrote an article for Forbes.com on this very topic. His article goes into greater detail about the changes and some ancillary issues. You can read his article here.
Also, I am including a link to the IRS Memorandum detailing the changes to the streamlined installment agreement program here.