Apple has just released the iOS 4.2.1 update on iPhone, iPod touch and iPad units, after a minor delay caused by an iPad WiFi bug. This update is particularly appealing for iPad users, who will finally be getting the long awaited iOS 4 support, that enables multitasking for third party apps, folders and AirPrint on their devices.

Tablet users will also get an unified inbox and support for fast inbox switching and threaded message view. Game Center support is also included, allowing users to play with their friends online, while AirPlay will support music streaming, plus photo and video sharing via wireless from the iPad, iPod Touch and iPhone, straight to the Apple TV.

AirPrint is another nifty feature, allowing iPad, iPhone and iPod touch users to print wirelessly to compatible printers, like the HP Photosmart, HP LaserJet Pro and HP Office units. iOS 4.2 also implements TV episode renting on the iPad via the iTunes App (30 day viewing window included). Enterprise support is on board, highlighting of words and phrases in Safari too and new device management capabilities.

At last, you get the Find My Phone feature for free, so you won’t have to pay to find your lost tablet, phone or portable player through a web-based interface.