The Family Support Payment Center
The New Jersey Family Support Payment Center oversees child support orders in the state. All money received from noncustodial parents passes through the NJFSPC before being disbursed to custodial parents. Effective with legislation passed in 1990, most noncustodial parents pay support through income withholding, so the NJFSPC usually receives the money directly from their employers after it's deducted from their paychecks.
The Probation Division
The court may exempt you from paying support through income withholding, which may occur if you're self-employed. If so, you'll pay through the Probation Division office in your county. Your check should still be made out to the NJFSPC, because Probation then turns the money over to the state center. In rare cases, you may be able to make your payment directly to your soon-to-be ex, but this requires special approval from the court, as well as her consent.
The NJFSPC is set up to accept online payments if you're not paying support through income withholding. ExpertPay allows you to make payments from your bank account, and Pay.njfspc.com accepts credit card payments.