25.4mb
About 25.4 MB in my first month. EDGE is slow in my city (Cincinnati) and was complained about many times when the iPhone was released.
I use Wi-Fi at home, work, friends, and many coffee shops and bars. I only use EDGE for email, it is too slow here for anything else, at least here. I noticed that in the Apple Store when testing the iPhone. In the store many of the iPhones (for some strange reason that the sales people could not explain) resorted to EDGE and not Wi-Fi, resulting in many missed sales.