Yahoo Lets Loose With a Boomerang - Automatic Website Testing
readwriteweb.com
readwriteweb.com
Stoyan Stefanov write weekly about performance on his blog http://www.phpied.com/ and actually just released "Web Testing Framework" at Velocity which is a YSlow plugin.
Nicholas Zakas wrote "High Performance JavaScript" (http://www.amazon.com/Performance-JavaScript-Faster-Applicat...) and does a ton of stuff for the Yahoo frontpage.
Phil Tellis (author of Boomerang) regularly blogs on performance on http://bluesmoon.info
I (sh1mmer) have done a bunch of performance related stuff with Aristus (now at FB) and I'm working on how network, consumer hardware and other holistic factors affect web performance. Expect some DNS related stuff soon.
Boomerang itself is actually a generic beaconing framework so you can use it to beacon anything but it also has a lot of bootstrap code as well for performance testing.
Phil has done some great documentation on how to do beaconing right to go with the framework and you should expect more of that.
However, until then, you can still measure the time from first-byte to onload by starting a timer at the top of your page. It's crude, but it works.