I am not a permanent visitor of blogs about SEO, but time to time i do check on this and this weekend i came across a post from April that states that Google now use site speed in their search ranking algorithms. So what does this mean? Nothing if you not care about how well your site ranks in google search results and a lot if you do.
Well, it seems like it doesn't influence TOO much the results right now (if any), but they started to use it, so things will change.
While site speed is a new signal, it doesn't carry as much weight as the relevance of a page. Currently, fewer than 1% of search queries are affected by the site speed signal in our implementation and the signal for site speed only applies for visitors searching in English on Google.com at this point. We launched this change a few weeks back after rigorous testing. If you haven't seen much change to your site rankings, then this site speed change possibly did not impact your site.

We encourage you to start looking at your site's speed (the tools above provide a great starting point) ? not only to improve your ranking in search engines, but also to improve everyone's experience on the Internet.

Posted by Amit Singhal, Google Fellow and Matt Cutts, Principal Engineer, Google Search Quality Team

So if you care, here is a short list of some free tools that may help:
  • Page Speed, an open source Firefox/Firebug add-on that evaluates the performance of web pages and gives suggestions for improvement.
  • YSlow, a free tool from Yahoo! that suggests ways to improve website speed.
  • WebPagetestshows a waterfall view of your pages' load performance plus an optimization checklist.
  • Many other tools