Exchange Ninja's
You may have seen this already from EHLO, but I have just registered and it looks as though this is going to be an incredibly useful site to for the inner depths of Ex2007 and the Powershell. Certainly going to keep an eye on this..!
https://www.exchangeninjas.com/
"This site was created to enable rapid sharing of tips, tricks and FAQs for the Exchange 2007 Beta. This is a wiki site, which means you should feel free to jump in and contribute by adding new content, editing existing content or simply by leaving comments on various pages. If you don't feel like editing content but have a request for content, just let the community know by asking a question.
To get started, please register (button on the right) and feel free to make changes - that's what wikis are for!
Also, check out the recent changes page to see what other people have been contributing. Browse the FAQs, Tips and Tricks and PowerShell Scripts sections to get more ideas."