You can get the official form for a Fee Waiver at http://www.uscourts.gov/uscourts/RulesAndPolicies/rules/BK_Forms_Current/B_003B.pdf.
However, you should strongly consider getting help from either your local aid society or, at the very least, the Bankruptcy Court's pro se office. Bankruptcy can be very complicated and its easy to make mistakes. Bankruptcy has several absolute requirements and deadlines that you need to comply with. Talk to your local legal aid first or try to find an experienced attorney.
You should go down to the federal court and visit the bankruptcy clerk. She can give you the packet of documents that need to be completed. The clerk's office where I practice offers pro se debtors a computer where they can complete them electronically. Our district also has a bankruptcy help desk where debtors can bring their completed schedules and have an attorney look them over before filing.
Here is a link to NJ's bankruptcy clerk's office:
If you are preparing your own Chapter 7 Bankruptcy Petition (a risky proposition in that a filed Chapter 7 case cannot be dismissed) you can file a motion to waive the filing fee or pay it in four installments. My office is not far at all from where you live. Initial consultation is free, call me so you don't create an unnecessary problem with a poorly prepared Chapter 7 bankruptcy petition.
Bruce C. Truesdale
Most people that are eligible for a fee waiver don't really need to file bankruptcy at all. You may want to look the "gift horse in the mouth" before jumping off the bankruptcy cliff. Hope this perspective helps!