Mail received quite a bit of attention in iOS 4, finally gaining some features that users have asked for since the original iPhone in 2007. Like its desktop counterpart, Mail in iOS 4 now has a unified inbox (though fret not, purists: you can still view individual inboxes as before) and threaded conversations. iOS 4 also brings the File Sharing feature (which originally debuted on the iPad) to the iPhone. For example, you can open a Microsoft Word e-mail attachment in a third-party app such as GoodReader or Documents to Go. Mail has also gained support for MobileMe e-mail aliases and multiple Exchange accounts for business and Enterprise users.

Again, Dan Frakes has .

Not by a longshot. The updated OS lets you use a real password instead of a four-digit pin to secure your iPhone. There's also a that now runs on the iPhone and iPod touch. You can make Bing the search engine of choice for the Safari browser instead of either Google or Yahoo, and there's now a spell-checking feature for Mail, Notes, and other apps. And as we've already mentioned, if you've got an iPhone 4, iPhone 3GS, or third-generation iPod touch, you can change your Home screen's wallpaper or use a Bluetooth keyboard with your mobile device.

As for enhancements to existing apps, Heather Kelly covers the while Christopher Breen outlines in iOS 4. Note also that you can now use the Spotlight search tool to look up things on the Web or on Wikipedia, and that Messages gets a few minor enhancements as well.