It may actually be time to upgrade to a Treo650, I'm preparing for a trip to Montreal (more on this later) and it really would've been great to have GPS capability. It appears that I'm caught in a catch-22 situation. There are GPS solutions for the 600, (ie SDIO, serial cable, etc). If you occupy the SD slot for the NMEA antenna, then you can't store the map data. Unlike headsets, they simply don't make a bluetooth adapter that would provide the GPS functionality, that is communicate with the GPS satellites to provide real-time navigation data. The resolution on the 600 would also make it difficult to use some of the more sophisticated graphical programs.
I thought about hacking into the E911, triangulation service, but the accuracy is very poor. Updates would be nearly impossible. Oh well, I do have all of the tub maps, and the ubiquitous currency converter. Though I won't be doing any driving, it would be cool to have turn-by-turn street map at my finger tips. Sigh... On a brighter note, I splurged on a pair of Scott-E-Vest cargo shorts. Mad cool.