If I have an non SIM locked BB with Cingular can I purchase a prepaid SIM overseas and use my blackberry there (Europe, Asia, MidEast)?

I know I can do it for phone service but what about the Blackberry service?

which is it... locked or unlocked. the title says unlocked, while the body says locked.

locked = no
unlocked = yes

If the unit is unlocked, you can use another sim for phone service only. You need blackberry service for email.

Unlocked=non SIM locked

So I'd have to sign up for voice AND BB service on a carrier for the second country.

i suppose.. just seems like an awkward way to say "unlocked".

I use my 8700c (Cingular) in places like Kuwait, Bahrain, Qatar and a few others. I have the international Data plan so get unlimited email/data. My BB is unlocked and from time to time use local SIMs. The only advantage to this is cheaper local phone calls but loose the data while I am using the local SIM. I do not believe you will be able to get a local SIM which will do phone and data as most SIMS for tourists are pay as you go. I just switch SIMs back and forth which is not convenient, but is the cheapest method for me.

If you can find a prepaid SIM with a Blackberry data plan it will work. I don't think any carrier offers those though - that's the real problem here.