I spent about an hour last night playing with the release of XNA Game Studio. My first impression is that someone at Microsoft needs to contract me to write some tutorials! Heh heh heh.
Actually, I'm greatly looking forward to incorporating XNA into a series of articles I'm pitching on GPGPU programming. Basically, I've written the same program in Ruby, C#, C++, C++ with OpenMP, C++ with assembly language, HLSL, and I'd like to add implementations in Accelerator, PeakStream, and any other GPU-based languages / libraries I can find. It'll be fascinating to see how the XBox 360 stacks up in "one design" racing. (BTW, as much as I love Ruby, it is slaughtered in this type of comparison.)
Say... I wonder if I could develop a tutorial that ran on the XBox 360 that combined audio-video / screencasts / etc. teaching how to program in XNA Studio. I mean, I know I could produce the tutorial, I just wonder if the "XNA Creator's Club" would allow me to distribute it (i.e., sell it) via XBox Live. Hmmm....