To further emphasize what 311evo said...(I own an iPhone 4 btw)
Apple does not make an iPhone 4g. Their latest phone is the iPhone 4 and it uses AT&T's 3G network (or Edge depending on your reception). There will probably come a time when AT&T goes 4G (if they haven't already) and Apple changes their phone to use this 4G network, but that's not the case yet. The phone is also available with a 16gig or 32gig flash drive. My guess is that given the asking price, this would be a 16gig model as those retail for $599 ($199 with a 2 year AT&T contract).
Not trying to kill your thread here, but you haven't really provided much info in order to sell this thing...plus pictures always help.
