I've been working a fair bit with Office 2007, from a dev perspective, for the last six months, and its great that a lot more articles, videos, etc, have started to appear, which makes the whole process easier to get up and going. This is especially important, as for many developers, Office dev is still a new area.
Here are some of my favourite resources:
Office Screencasts are a bunch of short videos (typically 10 or 15 minutes) just displaying a computer desktop (as opposed to the presenter) and focused on a specific topic. Quick and easy to watch. The SharePoint ones are delivered by an old friend of mine, Ted Pattison, who is an excellent presenter. Strangely, all these videos, plus a few more, also appear in Channel 9's "In The Office".
I attended the Office Developer's Conference earlier this year in Redmond, and so its great to see the videos from the sessions are on-line now. Although they are beta 1, they are still a good source of information, and the events had a very wide range of sessions, covering a whole host of Office based technologies.
David Chappell has just released a new paper entitled "Understanding Workflow in Windows SharePoint Services and the 2007 Microsoft Office System". I've known David for years and he has an excellent track record in taking complex topics and explaining them in a very simply and clear fashion, and this paper is no exception. I think workflow is one of the most interesting pieces of technology to have come out of Microsoft recently, and the marriage of Workflow and SharePoint v3 is a very powerful combination.
I know from personal experience that the process of setting up a full server system for testing and development can be a complex and time consuming process. I tend to use Microsoft Virtual PC, to make life easier, especially when it comes to sharing such environments. One neat alternative is to use the new 2007 Microsoft Office System Virtual Labs. They host the server machines remotely, using Microsoft Virtual Server I assume, which you can access via a browser with nothing to set up! they come complete with lab manuals and everything you need. There can be a bit of a time lag between pressing a key and getting a response, dependant on your internet connectivity, server load, One suggestion I have to ease that would be to print out the lab manual, so you don't have to switch back and forth between desktop windows.
And of course, don't forget the Office Developer Centre and the SharePoint Server Developer Portal, and a new Office System for Architects, with lots of links to articles, blogs, webcasts, etc.