Failsafes are simple devices and standard ones are available from model shops. These type just plug in between your Rx and speed controller/servo. Some speed controllers such as Vantecs and Robotechs have them built in so you dont need them on the drive. If you use a seperate Rx channel for your weapon then you may need one, but Rx relays such as the Electrolise (have a look at http://www.technobots.co.ukhttp://www.technobots.co.uk). If you are skilled at electronics then building one of these which simply switch a relay on with an Rx channel would be where to start. I built one with a MOSFET in place of the relay although I dont use it on any of our robots.

I use PIC chips for the bulk of my stuff.

I would be glad to help but I suggest you get yourself to a live event before you purchase anything and have a talk with roboteers. Thats the best way to learn and aviod making the same mistakes as we all have done while building.

Tip for the forum: Dont visit the Power Light thread Its enough to confuse anyone