Just replaced my old AIS Receive Only unit with a new Type B Receive and Transmit unit. My old one is free - first come first serve. It's 4 years old and been back and forth to Hawaii twice without a hiccup. See details on the unit at http://www.milltechmarine.com/Smart-Radio-SR161-AIS-Receiver_p_167.html
You'll likely need to buy an antenna splitter (http://www.milltechmarine.com/Smart-Radio-VHFAIS-Antenna-Splitter_p_171.html) and cable to hook to your GPS (I had it wired to a handheld GPS with NMEA 0183) to get it working.
You'll likely need to buy an antenna splitter (http://www.milltechmarine.com/Smart-Radio-VHFAIS-Antenna-Splitter_p_171.html) and cable to hook to your GPS (I had it wired to a handheld GPS with NMEA 0183) to get it working.