The below was copied from http://www.boatsafe.com/nauticalknowhow/radio.htm

Do I need a radio license? The Telecommunications Act of 1996 permits recreational boaters to have and use a VHF marine radio, EPIRB, and marine radar without having an FCC ship station license. Boaters traveling on international voyages, having an HF single sideband radiotelephone or marine satellite terminal, or required to carry a marine radio under any other regulation must still carry an FCC ship station license.

Those not exempted by the Telecommunications Act of 1996 must still have an FCC ship station license. A ship station license application is made on FCC Form 506, available from local FCC Field Offices, by writing to the FCC, P.O. Box 1050, Gettysburg PA 17326, or by calling the FCC Forms Distribution Center at (202)418-3676 or the toll-free number (800) 418-FORM. Forms can also be obtained from most marine electronics dealers.

Radios can be used immediately upon license application. The license is not transferable if a boat is sold or if the installed radio equipment is moved from one boat to another.

Effective 18 September 1995, the FCC fee for renewing or applying for a new ship station license is $75. Licenses will be valid for ten years.

If you wish to purchase a portable radio for use on more than one boat, only one license is necessary. When completing an FCC Application for Ship Station License (form 506), check "Portable" in block 10, "Type of License".

Do I need a permit to operate a radio? The FCC Restricted Radiotelephone Operator Permit is required for boaters having an HF radiotelephone, for boaters having a VHF transceiver and traveling in foreign waters, or where fitting of a marine radio is required by law (e.g. on boats 20m long or larger). There is a fee for this lifetime permit, but no tests are required in applying for this license. An application is made on FCC Form 753, available from local FCC Field Offices or by writing to the FCC, P.O. Box 1050, Gettysburg PA 17326.