It used to be that you had to unroot, but leave the phone S-Off in order to accepts the 2.2 update. However, the 2.2 release is out in an RUU format, so you can simply apply that. The process will mean wiping your phone, so be sure you have a good titanium backup to restore your apps. (NOT SYSTEM APPS!)

So, you have two options. 1. Go to Doug Piston’s site, listed in the Unroot section, and follow his instructions for unrooting your phone – just don’t go back to S-On. He tells you how to apply the 2.2 RUU.

2. Use a custom ROM, like Virtuous – which, with the custom kernel, will give you better battery life and remove all the 2.2 bloatware for you – and you’ll have 2.2 through the Nov OTA.

In either case you’ll have to wipe your phone first, so make sure you have that Android backup!