BalloonLinks
Other External Balloon links
Check out other people's rigs:
flickr photo group link
Pegasus
Utarc
Ham Ballooning
EOSS
High Altitude Glider Project
JP Aerospace
... Rockoons!
HABET - High Altitude Balloon Experiments in Technology
HARC - High Altitude Research Corporation
NASA Ultra Long Duration Balloon
NASA Antarctic Balloons
ABCs
(Amateur Ballooning Compendium)
fyi, here's another similar project beth found. not sure if this one has made the rounds yet.