ok so im aware if i purchase an unlocked iphone i can use it for making and getting calls, but can i use all the other features on the device such as Voicemail, SMS, MMS, Browser and youtube ect?
yeah, you can. just make sure it is also unlocked to be used with other GSM carriers, not just unlocked to get 3rd party applications. but yeah like i was saying all the other features should work just fine
if your going to buy one online, i would recommend getting it from www.importgsm.com
they carry both the 8g and 16g unlocked for any GSM carrier (including T-Mobile!)