There is an amazing amount of material available for SharePoint 2007. I have just started reading a new book from Microsoft Press called "Microsoft® Office SharePoint® Server 2007 Best Practices" from Bill English and Ben Curry.
I am impressed so far. It is great to see the first few chapters focused on planning and organisational change.
Also, Microsoft have just released the "Best Practices Resource Center for SharePoint Server 2007".
This facility is described as;
"To avoid common pitfalls and keep your Office SharePoint Server 2007 environment available and performing well, follow these best practices based on real-world experience from Microsoft Consulting Services and the product team"
Now if only I can find the time to read it all :)