This is one of those factors that as a marketer you want to know, right? 
Does the speed in which my site's pages load affect my Google ranking? 
Google is all about creating a great user experience.  And Google knows that the speed in which a web page loads affects user experience.
Aberdeen Group recently found that just a one second delay in response time can reduce conversions by 7% Akami/Forrester Consulting study determined that 2 seconds is the average amount of time consumers will wait for a Web page to load.
Google Engineer Matt Cutts just recently indicated that page speed will be a factor that Google will be utilizing to determine rankings in the future.  Of course, Matt referenced some great resources to help webmasters at: http://code.google.com/speed/articles/  But you may say, I'm not a webmaster- I'm an SEO or online marketer!  Well, the first place you can start is to setup (if you haven't already) Google webmaster tools.  Once installed, you can review your site performance.  Here's an example: In this example, you can see where there were some speed issues in October that were resolved. If you want an optimal user experience and be prepared for when Google and other search engines include Web page load speed as a factor to rank your site, you will want to ensure that the speed your Web pages load are tracked and monitored.  So the short answer is no, not yet, but likely coming soon. Our Search Engine Optimization practice area at interactive marketing agency, WebsiteBiz, is constantly evaluating emerging and eminent changes to ensure our clients SEO results are maximized.  Want to hear directly from Google Engineer, Matt Cutts?  Watch the video below and share your comments.