Yep. That was reported on macrumors and justanotheriPhoneblog yesterday. Seems like a lot of phones to order for only the second half of the year. Maybe they're expected increased sales with 3G capabilities.
I'm not sure how fast it's going to be on an iPhone but when I had 3G on my Motorola RAZR V3xx and I used the phone to get internet on my laptop it absolutely flew. It was almost as fast as my home DSL. It would be awesome to have on an iPhone.