In Reply to: Cell Phones / Sim Cards posted by MikePin on Friday, 22. April 2011 at 23:28 Bali Time:
It depends on who your carrier is in the US as what freq your phone is on. You could probably google your phone model and find the freq it uses.
There are varying freq between the carriers in Bali and the US.
Simpati 3G runs on the 2100 freq, while the non 3G freq is 900/1800.
Your phone will need to be unlocked from your carrier.
Depending on time avail before you leave, you can purchase cheap phones in china that run on quad bands, that way you can be covered for any further trips anywhere around the world too.
I have included a link below to site which gives you coverage maps and tells you what freq your carrier uses.