Fred Eady in Servo Magazine had recent articles on CAN bus using PIC. The Mikroe CAN systems is probably the easiest system.
If you have never programmed a microcontroller, Parallax (sold at Radio Shack) makes the Basic Stamp Homework board for about 79 bucks. While not necessarily up to a any complex and reliable NMEA 2000 device, it is a great product for the price. Nice tutorials on sensors (temp and light) as well as servo control.
www.parallax.com.
Thanks
Unzinced ships sink at slips. yep