hi gal (you know who am i, but please don't disclose it here; as i wanna remain anonymous here

)
getting from maxis is a little tricky because maxis has a tendency to sell their iPhones on a contract (they tend to reap more by doing so) as opposed to outright.
however, as far as i know, you can get the 8GB 3G (not 3GS) variant without much hassle.
you also get from singapore (but again, i don't think that they sell them without contract)
having said that, you can off course, get them from those third party mobile phone stores (which will rip your wallet off or worst; without warranty)
you can definitely try your luck, popping into maxis stores around the country and ask if they are willing to sell them outright (if they do, then it is your lucky day)
both singaporean and malaysian (maxis) bound units are unlocked by nature and hence you can of course use them with a DiGi simcard, without any complications
Nok, allow me to add that Maxis is now selling the iPhones outright without contracts, probably due to lesser demand in view of the imminent new model coming soon. But the 32gb is in abundant with 16gb available in certain outlets only.