Great timing!
I was about to say the problem with these things is that I can't test dev projects that are behind an authentication wall until I'm ready to let Google in. Then I poked around and found out that their tool will actually do HTTP Auth. I just put a site on development server behind HTTP Auth last night.
Great report - some items not being gzipped. Why? Don't know yet, but I'll find out.
For whatever reason, I find this more handy than the Google and Yahoo plugins.
