As many expected, iPhone OS 4 will bring multitasking to the table, a much needed feature if Apple is to keep its mobile OS relevant. App developers will have access to seven new multitasking services, including background audio and VoIP. This means apps like Pandora will be able to stream music in the background, while VoIP apps can receive calls regardless if the iPhone is asleep or if the user is doing something else.
iPhone OS 4 will also include Folders, another much needed feature and one that brings the OS up to par with competitors like Android. The way it works is users will drag an app icon on top of another to automatically create a folder. The new folder is then given a name based on the App Store category of that app, though these can be renamed. By utilizing folders, users will be able to install and access over 2,000 apps on their iPhone.
For email duties, iPhone OS 4 introduces a Unified Inbox. This will make it so users can see messages from all email accounts in a single box. Messages will also be threaded by conversation, and email attachments can be opened with compatible apps from the App Store.
Other features include iAd, Apple's new mobile advertising platform; a Game Center somewhat similar to Xbox Live in that users will be able to invite friends to play a game, start multiplayer games through matchmaking, and even track achievements; and a Mobile Device Management service of interest to IT gurus, which can be integrated with third party servers to wirelessly configure, query, and wipe or lock managed iPhones, as well as enable enterprises to securely host and wirelessly distribute their own apps to employees.
Not all features will work across the board. You'll need at least an iPhone 3GS or third generation iPod touch (late 2009 models with 32GB or 64GB) to use multitasking, so if you're rolling with an older mobile device, here's your justification to upgrade your hardware.
The iPhone OS 4 beta software and SDK are available now for iPhone Developer Program members at developer.apple.com . For everyone else, the update will roll out this summer, with a version coming to the iPad this Fall.