NOTE : We haven't test this yet.
STEP 1 : Download iOS 5 beta 7 on your iDevice.
STEP 2 : Download iTunes 10.5 latest version.
STEP 3 : After that Install iOS 5 beta 7 via iTunes and you can jailbreak it with Redsn0w 0.9.8b7
STEP 4 : Now you need to delete a key and string from the filesystem in order to activate the iPhone, iPad or iPod Touch on iOS 5 Beta 7 without Developer’s account. To access the file system use a software named iFunbox.
STEP 5 : Now launch iFunbox and go to this path :filesystem/library/coreservices/systemversion.plist. Right click on the file and then open it in notepad. Once opened, locate and remove:ReleaseType beta . Save the file.
STEP 6 : Almost done, now reboot your device and since it’s jailbroken, you’ll need to boot it tethered using redsn0w. And that’s it, you’ll regain access to the iPhone or other iDevice and your cellular service will also work if you are on an official carrier.
Okay now you should enjoy iOS 5 beta 7, let us know if the guide worked good with you or not.