I've had great sucess with my SPVM5000 and my Polstar GPS for navigation using Pocket Streets and TomTom and my SPVC600 for Geoblogging with Sharpspace

A company called Benefon has launched a cell phone with a built in GPS receiver — nothing new there. However, this particular GPS cell phone, called the Twig, does something extra. It can send your GPS coordinates to another Twig owner and then that person can navigate directly to you using the preloaded navigation software. Sounds like this could save a lot of time and effort when trying to explain to theyour drunk mates which pub your in. The phone will cost £330 in the UK, or about $625.