The Mint-Trak300 is a GPS receiver combined with a VHS Micro-Trak300 transmitter for APRS communication.  The system will transmit GPS coordinates via APRS on 144.39MHz.
 
With the recent release of VHS/Byonics Micro-Trak300, and with a Navman GPS board just waiting to get utilized, I had a great project waiting for me to build another APRS system to replace my bulkier Pocket Tracker.  At just 1" x 3" the Micro-Trak300 (V1.0) is just about ideally suited for rocketry.  The Micro-Trak300 is a nearly complete radio transmitter and APRS packet converter.  The only assembly required in this "kit" is to solder the Micro-Trak300 board and Tiny-TrackSMT board together, supply power and GPS connections, and you're ready to go.
 
I used Navman 12-channel GPS board salvaged from an older Palm-Pilot GPS system which fits perfectly in the bottom of the mint tin (instructions for hacking the NavMan GPS board can be found here).  I used a piece of foam to separate the GPS from the MT300 which sits on top.  The GPS antenna is mounted to the underside of the mint-tin (the cable connects to the antenna through a hole in the back of the tin).  The MT300 antenna cable connects to a BNC connector on the top of the tin. 
 
I sat on this project for a while hoping to come up with a very small power source that could fit inside, but finally decided just to finish the project and mount a 9V battery holder on the top of the tin.  A small plastic window on the front of the tin allows me to see the status LEDs.
 
I was fortunate to find some resources on the web that described how to remove and rework the Navman GPS board using these great instructions from GPSnuts.  I also referenced these instructions from QSL.net for mating the Navman board with a tinytrak.  In my case, I used the SMT version of the tinytrak so I had to modify accordingly.