Matt Cutts, who for those who don’t know is head of Google’s Webspam team and seen as the oracle for all things Google,
At around 2:38 in this video from Web Pro News interview of Matt Cutts where he discusses the new Google site speed tools that you can use to make your site faster. The toolkit is more extensive than YSlow but the end goal is the same – identify the slow points in your site and help you improve it.
The gem in that interview was when Matt revealed speed might be used in the futureas a metric in rankings, as it’s already integrated into Adwords. It is in line with Google’s desire to continually improve user experience and whether or not it is a ranking factor is really irrelevant, you want a fast site anyway.