1. Simply get the beta 2 OS file
2. Make a backup of your iphone data through itunes , as daily backup procedure
3. In itunes, press and hold "Shift" and click "resotre" , select your beta 2 file
4. Wait, have a dirnk
5. Done, beta 2 is installed


you can restore the app, song, that you have just backup before the upgrade.
of course you need to be a developer to get the beta works.

enjoy it.

Why bother with doing a restore? Update works just fine from beta 1 to beta 2.

Just like how to select the beta 2 file using restore, in iTunes, hold "shift" and click on "update or check for update" and then select the beta 2 file. No need to do the extra step of restoring the backup.

if it were me I wouldnt backup the phone/restore from backup at all. id restore to beta 1, then goto beta 2.

has anyone done 2.2.1 to beta 2?

I did,
The secret is to disconnect from the internet before upgrading
Good luck!