It is now possible to apply online to be a “CAT” at Leeds or Reading Festival 2006. CATs are Campsite Assistant Team Volunteers at the Reading & Leeds Festivals.
As far as I know you work three 8-hour shifts, all of which you have a strong say in when they are and after that you can do whatever you like. You have to put down the deposit for the ticket before you are let in, so don’t think about getting off free 
You can apply here: http://www.dcsiteservices.com/application/catApplicationPage001.asp
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