Looks like the Motorola Xoom has already been rooted. It's been released for just one day and Koush as we all know him by has got a Xoom Root Guide already posted online. Since the Xoom is a Google Experience device he said it was a pretty easy device to root once he got the proper support for full fastboot. It ships with fastboot support but it is limited. While your here read about the Xoom Unlocked for Flashing also.
Instead of getting into all the juicy details and trying to explain it. I'll just send you over to his instructions so you can get started on Rooting your brand new Xoom right away. Check out the via link at the bottom of the page. Otherwise feel free to read up on any of our other Xoom stories. Here are a few:
Data plan no longer required with Xoom Purchase
Motorola Xoom in Action Commercial
Moto gets a lawsuit over the "Xoom" name