I am fairly new to the GSM world, and have a few questions. If I get an "unlocked" version of this phone, and presently have Cingular GSM service, what would I need to do, to scrap my current phone and get this one activated? Would I have to take it to Cingular to get it programmed or just plug in the SIM card from my existing phone? Also I've noticed this one operates on 900/1800/1900 MHz as opposed to most Cingular phones (850/1800/1900). Thanks for your insight,
With Cingular, GSM 850 is required for most parts of the country. If you're in NYC or California, and don't travel much to other states, you could use the P900. But pretty much anywhere else and you're out of luck. ☹️
That's not an issue with T-Mobile, and not a major one with AT&T. It's only Cingular that relies heavily on GSM 850 for primary coverage.
It's too bad the P900 isn't quad-band like the Treo 600...
But if that's not a problem for you, you can just get an unlocked P900, and all you need to do is pop in your SIM card. That's it! That's the beauty of GSM and SIM cards!