One final point on the cost. First, we don't know what the true cost will be, because we don't know about the most important factor in the cost of a phone: Rebates.
For example, if I go to Sprint's phone site, and look at the base cost of the various phones in the "PDA phones section" I see that the base cost ranges from $649.99 for the Treo 700p and the Treo 700wx, down to $399.99 for the Blackberry 7130e. The reasons you don't pay much are because with various layers and rebates, the potential price ranges from $399.99 for the PPC-6700, (no mail in rebate on that sucker) to $149.99 for the 7130e.
So at the high end, a PPC-6700 is only a hundred bucks cheaper than a 4GB iPhone, and I'll tell you right now, while the 6700's a nice phone, it's not even close to what an iPhone can do other than direct Exchange connectivity. It sure doesn't have 4GB of space unless you buy the SD card, and a 4GB SD card will drive that 6700's cost to just a bit above the cost of the 4GB iPhone. (Let me also say that I have yet to get Pocket Outlook to let me send mail via authenticated SMTP with IMAP accounts. I am so not impressed with Pocket Outlook, any version. I'm sure there's some way to do it, but if so, it's far too counterintuitive for me to mess with.) Looking at Verizon and Cingular, the story's about the same there. So much for Ballmer laughing about how much the iPhone might cost.
Again, I'm still not planning to switch. I like Sprint. I like them a lot. I like them enough to put up with really bad phone UI, because their service, both RF-wise and person-wise, has been pretty good. Not that I wouldn't switch for a phone, but I'd have to see all the details, which I don't have right now.But after seeing the iPhone, I'll tell you, I kind of wish my work provider around June would be Cingular.