errmmm... The only this you really need is a programmer.
There are a couple of FW available. look here to see a summery:
http://www.rcgroups.com/forums/showpost ... ostcount=1
eePe is also not essential. You can use Winavr but eePe does make things simpler for those who just want to use the FW.
So to make thing simpler - once you have your programmer installed. Download eePe an the latest revision of the FW of your choice. Use eePe to "burn" the FW to your tx.
There are a couple of tutorials on the er9x homepage that are worth reading. They will make your life easier
Feel free to ask a question here if you get stuck.
Erez