You are confusing the new software update for the original iPhone with the new iPhone.
To answer the OPs question, yes, you do need iTunes 7.7 and the 2.0 update to access/use the App Store. The App Store can be accessed from either the iPhone 3G or the original iPhone with the 2.0 update.
I have two phones bro' & am comparing, not confusing. I should've been more clear. I really think that the App store BLOWS ,right now anyway & that even though the new 3g has some perks & there are a couple of apps I like, I just cannot justify updating mine right now.