The replies here i find to be kind of juvenile. i geocache with just my iphone sometimes when im out of town and forgot my GPS but it is so much nicer to use a GPS unit that can get you withing 6 feet. Im only using a cheap GPS but if you really wanna get lost with your geocaching try using a phone to find a cache in the backroads of Montana. However im sure urban caches will be just fine with a phone.