Well, I'm Dee, a 20something year old programmer near Southampton. Not only do I read xkcd, but I'm also a geo geek and have contributed a lot to the local OpenStreetMap project. I also enjoy photography of abandoned buildings which also takes me to many weird and wondeful places!
Having now found out about geohashing (I never thought the idea would take off when i saw the comic) I have come to a few meetups, the first being 2009-09-27 50 -1.
Originally I was using an ancient handheld GPS, but after losing my phone, I now have a nice shiny HTC Hero with a built in GPS and the incredibly useful Geohash droid.