I just wanted to post this info as it has taken me serveral weeks to setup my Treo 650 so it worked on the Siminn network in Iceland....
www.siminn.is


NR:1
PREFERENCE - CENNECTION..

Service : Internet GPRS (This should come when you insert the SIM)
Connection : GPRS
User name : emty
Password : emty
APN : gprs.simi.is


NR:2
Then I hade to make another... (When in internet GPRS press modify)

Service : MMS (manual name)
Connection : GPRS
User name : emty
Password : emty
APN : mms.simi.is


NR:3
In the MMS program I went into PREFERENCES - NETWORK and in NETWORK CONFIGURATION choose MANUAL and then EDIT.

Message center number : +3548900100 (automatic)
Email center number : emty
MMS Gateway Address : 213.167.138.200
MMS URL : http://mms.simi.is/servlets/mms
NetworkProfile : MMS (see NR:2)



I hope this can help somebody....
Regards from Iceland, Jon