I was in Israel last week with my unlocked Verizon 8830. I have a United Mobile SIM card which I've used successfully in a number of countries. In the 8830 set to GSM or Global, it accepts incoming calls using this SIM card for calls made to that number. In GSM only, it will not make outgoing calls, but will receive calls. To use the web, send or receive email or BlackBerry Messenger, the mobile network needs to be set to Global or 1XEV since the compatible system for Verizon in Israel is CDMA. When it's in either of those modes, the phone application using GSM does not function so outgoing calls end up using the CDMA system at $2.00/minute rates. I called United-Mobile to see if they could come up with a solution. They said I needed to locate a United Mobile folder on the BB. I could not.
To see if there was some problem with the phone, I inserted a local SIM card and it functioned perfectly. So now I'm wondering if the problem has to do with the local system being CDMA instead of GSM . . . although there are two major GSM systems in the area.
Any ideas?

If I'm correct the 8830 by default will always check first for CDMA, if it find a CDMA network it won't even try getting a GSM network, don't know if there is a way to change that.

Regards