Thought I'd create a thread where we can share profiles and follow each other.
Strava is a great free app works well on my iPhone 4 and i assume it's available for most phones. It tracks your trails and puts you on global leaderboards, timed segments etc. I've been using it for a while now and the only downsides that i can think of is the maps aren't very detailed and ypu can't export the trail as a gpx file. Or any file for that matter.
Here's a link to my profile