Here is a detailed description of how to configure the native MMS application on the iPhone 3.0 OS
http://blog.vinko.com/2009/06/15/mms...-on-iphone-3g/
APN = wap.digiceljamaica.com
MMSC = http://mms.digicelgroup.com
Username = wapuser
Password = wap03jam
MMS Proxy = 172.016.007.012:8080
Let me know if this works.