you would be able to find instructions on rooting a 1.5 eris and you end up with a rooted 2.1 eris on XDAForums.com or androidforums.com those both get a lot more users and a lot quicker responses. Plus i'm sure XDA already has the instructions somewhere.
But i'd just like to point out if you have the leaked 2.1 you may not be able to root. I know as of Friday you couldn't. But idk i haven't checked today or over the weekend or anything. Good luck.
I don't know if you guys understood what I said correctly. I was saying that if you root you phone, and you don't disable OTA Updates, your rooted phone will receive the OTA Update when it comes out. And if you choose to install the update, it will completely remove root, and make your phone ONLY run on the OTA Update. Which in other words, means your phone's warranty won't be voided anymore.