Thinking of getting one of these Nike + do dahs, as I've started doing a bit of running. Anyone using one? Are they any good? Can they be used without compatible trainers (thinking of just straping one to my merrels as I generally only run off road)?
There's an adaptor you can get to use the sensor with other shoes - marven makes it (see here for a picture: http://www.macdailynews.com/index.php/weblog/comments/10974/)
I've used one, they're a bit of a gimmick really - quite entertaining, but in no way necessary for running. I suppose if you're religiously following a plan they could be quite handy.
I have one and I quite like it. I think it's not super accurate, but gives you an idea of the distance you cover on different routes. I use it with Asics shoes. I used to have a plastic gizmo, bit that broke and I lost the sensor, so now I use one that's a sort of neoprene and velcro pouch similar to the one mentioned above, that is attached to the laces, and seems more secure.