The UK High Altitude Association is a group of like minded people with a common interest in all things high altitude…. especially balloons. A great source of detailed information and FAQs http://ukhas.org.uk/
Also if you are actually considering having a go yourself then get onto the Irc high altitude channel, a dedicated chatting environment where I had many detailed questions answered instantaneously, I could definitely have saved time by visiting here sooner! http://webchat.freenode.net/?channels=highaltitude
Finally we would like to say a big thank you to the Chemical Engineering department at Queen’s University Belfast for all their support and helpful advice concerning the usage of Helium gas.
Balloon, 35kg breaking strain nylon and parachute : http://randomsolutions.co.uk/top.htm
Very helpful and by far the cheapest supplier of weather balloons that I could find.
Radiometrix NTX2 Transmitter: http://uk.farnell.com/
Flight computer PCB and PicAxe 18X chips: http://220.127.116.11/epages/Store.storefront/?ObjectPath=/Shops/Store.TechSupplies/
Garmin GPS-35 : £15 Ebay