Yes. Assuming your phone is unlocked, you can just buy any sim and stick it in.
The shop/kiosk will generally look after the registration (varies country by country, but often a copy of your passport required) which makes the process that much less painful then they'll sell you a package for calls data etc.
In my experience this is best done at airport as they're more geared up for foreign tourists, but any shop can assist.
#2somtam2000 has been a member since 21/1/2004. Location: Indonesia. Posts: 8,062