The manual you will receive here, is good enough.

I learned today, that Haynes will start selling the XT manual in May 2011, it can already be preordered (around 35$):

Name:
Yamaha XT660 & MT-03 Service and Repair Manual: 2004 to 2011

Wish I knew, what it has inside, sometimes the Haynes manuals are with better pictures and explanations. I have had different bikes and always had two service manuals.