Apple Insider posted this article on supposed software updates the iPhone will receive before 10.5 is released in October. If they are correct (especially the file browser and mini-iChat parts), I won't feel so bad about waiting until January for my Verizon contract to expire. But either way, some interesting stuff...
They also mention having iWork on the phone eventually and also support for Flash.
http://www.appleinsider.com/articles/07/07/01/apple_planning_host_of_iphone_updates_before_leopard_release_source.html
Some of these updates may arrive within weeks. A true instant messaging client described as a mobile version of iChat, will arrive "very, very soon" and certainly before Leopard, the designer says. Customized ringtones were also set to appear within the same timeframe.
But fall 2007 is when the iPhone's features are set to expand in earnest, he adds. The iPhone will not only gain a disk mode for transferring computer files but should also receive a full-fledged file browser that lets users store and open documents. Its omission from the iPhone software made available in June was supposedly made primarily because the company wants a fully developed browser very similar to that found in Mac OS X Leopard, including the option of Cover Flow browsing.Leopard itself will also allegedly include hooks for the iPhone, opening an enhanced file window in Finder for dragging files to and from the device. Like the iPod shuffle, users will be able to set aside a certain amount of the iPhone's flash storage for iTunes content and the rest for general data.
They also mention having iWork on the phone eventually and also support for Flash.

http://www.appleinsider.com/articles/07/07/01/apple_planning_host_of_iphone_updates_before_leopard_release_source.html