15 postage stamps will be released on May 25, 2007, which as STAR WARS fans know is the 30th anniversary of the release of the first STAR WARS film. (OK, I officially feel a little old now...)
You can view all the stamps and vote for your favorite here.
The Han Solo/Chewbacca stamp is my favorite (of course). The Yoda and Princess Leia/RD-D2 stamps are nice too.
I would suspect the USPS stands to make a large sum of money from STAR WARS fans who will buy sheets of the stamps to save rather than use.
My daughter has spotted one of the R2-D2 mailboxes near the Shrine Auditorium in Los Angeles, but I haven't seen one yet...