I use the velocomputer on my BlackBerry Storm 2. It doesn't have an immediate display of the path you are on, but it does output quite nicely into google maps and earth. It'll record distance, speed, acceleration, cadence, and position. More than decent for a 15 dollar app.

I work for them but I also use it so, I hope this isn't solicitation. Lemme know if it is and I'll delete the post.

Rob