I use an iPhone and an application called RunKeeper (It has options for cycling, walking and hiking too). It has two levels; a free version or a Pro @ $9.99 version. The Pro gives you the added feature of an audio feedback. Using the iPhone's GPS it tracks your route, time, speed/pace, distance. Further it downloads the info. automatically to a website: http://www.runkeeper.com/

It is an awesome application, also MapMyRide is available as an iPhone application. I prefer the RunKeeper. With the iPhone I really have no need for something like a Garmin.