Matt Cutts has recently discussed how speed will be a more important factor in organic ranking and adwords quality score.
Here is a blog + video about it - http://searchengineland.com/site-speed- ... ctor-29793
And here is a link to the google speed resource area http://code.google.com/speed/ This includes coding tips and a js library for improved page loading.
Really advisable to get ahead of the curve here because Google are clearly stating that they will reward faster sites (both with organic ranking and adwords cost) because they provide improved user experience.
Cheers,
Jon