Since Apple hasn't given us a comprehensive list of all the little changes in iPhone 3.0, users have taken it upon themselves to compile the treats they've found in the new software, some of which are actually quite nice.
The MacRumors forums have a couple of ongoing, constantly updated lists, though of course we can't verify their massive efforts. Here's part one and everything since part one of their informal list, and a slightly more structured list can be found here.
If you want something a little easier to read, iPhone User Guide has posted a nice and simple list of (at the moment) 113 new updates they've found, from font changes to new customisation options to iPhone 3.0's ability to display album information when the device is locked.
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