The Public Service Loan Forgiveness program (and here) started July 1, 2009. There is more information, and links, at this Law School Academic News blog post. (Note: the program is not just for law students.)
This is a very new program and I recommend you run a search for the most up-to-date information. The following Google searches will bring up dot gov or dot edu sites, which are the best place to begin for very new educational benefit program information. You can also check with your financial aid office, if you are still a student.
Search string: Public Service Loan Forgiveness program site:.gov
Search string: Public Service Loan Forgiveness program site:.edu