Title says it all. It also includes the ability to skip the beta timer, meaning your beta won't expire. Not for me, but this seems like a solid way to try iOS 5 without too much risk.
http://www.idownloadblog.com/2011/08/18/sn0wbreeze-beta-5/
Interesting, not worth the risk IMO. Plus tethered on iOS 5 beta is no good. I find that my battery life is the best if I reboot the phone every morning.