It's really pretty gimmicky since they're just going to microscopically inscribe the thousands of names on a single microchip, but at least it's free. (And at least it's not something blatantly fraudulent like those certificates claiming a star or a crater or whatever has been named after you.)
When you sign up you get a virtual ticket and it will supposedly keep track of "frequent flyer" miles for you, which will be redeemable nowhere :)
Here's the link to the original post:
http://mars.nasa.gov/news/whatsnew/index.cfm?FuseAction=ShowNews&NewsID=1725
And here's the link to my "ticket":
http://mars.nasa.gov/participate/send-your-name/orion-first-flight/?cn=558536