Apple has released iOS 4.0, the renamed OS for their portable devices like the iPhone and iPad. This version will work on the iPhone 3G, iPhone 3GS, and upcoming iPhone 4, but not on the original iPhone. Some of the new features require an iPhone 3GS or better.

There is no cost for the upgrade and you can download and install it all through iTunes. While the list of benefits and improvements is long, there are also some bugs of the annoying variety. My advice is to wait until Apple fixes some of them in a 4.0.1 update (or whatever they call it) before taking the plunge.

You can read more about the upgrade and its new features here.

[Written by Kem Tekinay]