I use IM3 Indosat on my iphone, works but is slow and cuts out for a day here and a day there, pay is by use and its cheap coz not many mb's get through in the end.  You need to put in the the network and cellular data or it wont work.  All the sellers know jack about this so go to the main Indosat shop to get it set up.  All the other countries I have visited just require the sim in and off u go.