Some of the best pictures:
You can find the rest over at http://www.srcf.ucam.org/~hmh33/flight_mihab/
Here are a few construction photos, I'll try and add more info later
And here are some launch & recovery pictures
The microcontroller was programmed with Bascom-avr you can find it over at http://www.mcselec.com/
atmel mega8 from http://www.active-robots.com/products/controllr/atmel-avr.shtml it's a bit pricy but they sell boards with ISP sockets and DIL headers which is very handy.
Here is the source code if anyones interested intellballoon2.txt