No, indeed the 3G plan is likely to cost $10 (10x24 = $240) more than the 2G plan...although you're paying for 3G speed...and 3G coverage ain't ubiquitousl in the States either.
Another rumor is that you'll no longer get free SMS bundled in the data plan...$5, $10 or $20 a month more...
Me..I can't wait...selling my 2G iPhone, sold my 5th gen iPod...getting ready for a nice shiny 16GB 3G iPhone...been a happy iPhone user for almost a year now ..in fact I'd be happy to fork over $100 more for 32GB
