The U.S. Indian Health Service is one of the larger loan forgiveness programs, but there are specific rules involved. They have a website you can easily find by doing an Internet search. Many loan forgiveness programs are through local, state or federal health agencies, so the public health departments are one place to start looking for these programs. Some hospitals also offer them. You just have to call their human resource departments and ask if they have them. Another place to look for information in your state hospital association. They will sometimes know which facilities are offering loan forgiveness programs. Other organizations to query are your state nurses association and the state board of nursing.
You're state also might offer one. I found Florida's through Google a while back and applied.
For those in Florida here is ours: http://www.nslfp.com/index.htm
It was funded when they tripled the cost of our license a few years back. At the end of 2008 I should be getting $4000 of my RN to BSN loan paid off.
This info should also be provided to you by the financial aid people at your school. I had loan deferments for unemployment after I left school and in the past for military service. I never was told about or looked into loan forgiveness programs. Ask at your school. They have an obligation to inform you. Good luck.
Note that most "loan forgiveness" is not a "we'll pay off your entire loan for you just because you're a nurse". Usually they pay off increments, for example Florida's max is $4000, plus you have to work in specific hospitals/clinics. I have to work one year at my current facility (a not-for-profit hospital that is on the list of those they will reimburse - it's a small list) then they will pay off $4000.00. If there's a balance after another year, it's another $4000.00 etc.
People sometimes get the wrong idea and think their entire debts will be immediately wiped clean.