Is their any good mod kits to convert a Bridgeport to a CNC machine?

Tons, especially if you're talking about a Series I Bridgeport. Just do a google search and you'll find hundreds of different companies that sell CNC kits for BPorts.

http://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=bridgeport+cnc+kit