I'd be participating in a support Webcast on Windows Vista Upgrade pathways sometime on July 25th at 10:00 AM PST. I will not presenting it, but might come on voice during the Q & A. I'm happy about doing this as this should be a good opportunity to help customers understand the various Vista upgrade options and especially the common mistakes made. If you need something specific added, feel free to ping me and I'll try and address the same on this Webcast.
EDIT: Almost forgot. You can find the Webcast at this link.