I have Blackberry service here in Cayman but with the advent of the unlimited international data option w/ Cingular and T-mobile, it seems to make economic sense to change to a US-based service provider. Let me know if I am on to something with my particular example (data only - no voice):

Currently pay $50/month for unlimited local service in Cayman. GPRS usage anywhere else in the world costs ~1.8 cents per KB or ~$18 per MB. An unlimited Blackberry data plan from T-Mobile is $30/month and the unlimited int'l option is another $20, for a total of $50/month. The same unlimited options with Cingular comes to about $70/month.

I frequently travel to North America and several other continents so my GPRS roaming bills have been quite high, certainly more than what I quoted above. I also have a T-mobile pre-paid phone that works fine for my frequent trips to the USA but would gain a US-based number for the blackberry as well if I choose to have 20 cent/min. calling, which would reduce the need to carry two devices.

It seems to be a no-brainer and I am curious if any other Blackberry FT's would agree.