Image taken from Industries have released their GPS sensor; it’s now available on sale for $105 US. It’s the world’s first GPS sensor specifically made for the NXT.

I’ve had one of these beauties for a while now and it’s a lot of fun to play with.  You can read all about it on this page here: [LINK], which includes downloads of drivers for various programming languages (including my ROBOTC drivers) and a nice user guide.