The latest local R user group to form is located in Houston, Texas. The first meeting of the Houston R Users Group is tonight at Rice University (in conjunction with the Houston chapter of the ASA). R hackr (typo intended!) Hadley Wickham will be giving a presentation on writing R packages, and you can check out the slides on his SlideShare page. If you're in the Houston area, be sure to sign up to the Meetup group to be notified of future meetings.
Meetup.com: Houston R Users Group