Hot on the tail of the recent iPad launch, Apple also announced a major upgrade to the iPhone operating system. In a nutshell, there’s some really nice stuff coming down the pipe. Here are some of the highlights from today’s press event:

• MULTI-TASKING – This was one of the last showstoppers keeping me from jumping on the iPhone bandwagon. This is not a full implementation of multi-tasking, but it still looks pretty sweet and may actually be a better implementation due to improved battery and resource management. To do this, Apple will make 7 new services available to devs:
  • Background Audio – Apps like Pandora can continue streaming audio while you use check your email, browse the web, purchase the song from iTunes, or use any other apps.
  • Voice Over IP – Apps like Skype will be able to maintain connectivity while using other apps as well as when the iPhone is locked. You will remain online and can receive calls, even remain on a call while switching to other apps.
  • Background Location – GPS apps like TomTom can continue tracking your location and giving you directions while running in the background, though this continues to use more power and is better suited to in-car use where the iPhone can be plugged in. Social networking applications like Loopt and FourSquare can use cell towers via AGPS to track your general location in the background, using much less power. Location awareness can be enabled/disabled on a per-application basis.
  • Push Notifications – Apps can use this feature to have news alerts and score updates pop-up as messages on the iPhone by using a 3rd party server to send the messages via Apple’s push notification service which runs in the background
  • Local Notifications – These work just like push notifications without needing a server; applications will be able to generate pop-up messages locally.
  • Task Completion – Tasks that take time to complete, such as uploading photos and video, can continue in the background and notify you upon completion.
  • Fast App Switching – This improves on an application’s ability to maintain state and save all of its data when switched to the background, and be restored exactly as it was when switched back to the foreground.
• Folders – This feature seems very Windows-like, but after seeing some people’s home screens, it is very much needed.
  • Apps can be stacked on one another to automatically create a folder
  • Folders get automatically named based on the app’s related app store category and can be changed
  • You are currently able to see 180 apps across 11 pages; if you replace them all with folders you will be able to see > 2000 apps
• Enhanced email – Really good stuff if you have to manage multiple email accounts
  • Unified Inbox consolidate multiple accounts into a single location including support for multiple Exchange accounts and most web email services
  • Fast Inbox switching if you want to focus on individual accounts
  • Ability to open attachments with an app from the app store
  • Ability to organize by thread
• iBooks – Looks identical to iPad version (only smaller)
  • You can buy books once and read on iPad or iPhone
  • Automatically syncs page and bookmarks wirelessly
• Enterprise-specific features
  • Email and data encryption
  • Remote device management
  • Wireless app distribution
  • Support for SSL VPN
  • Multiple Exchange accounts (previously mentioned)
• Game Center – This looks like a blatant rip-off from Microsoft’s Xbox Live, but I can’t argue it seems like a feature many iPhone gamers would love to have.
  • Adding a social gaming network
  • Matchmaking feature
  • Online Leaderboard
  • In-game achievements
• iAd mobile advertising – This looks REALLY interesting. It not only opens the doors for companies to come up with new, engaging advertising campaigns, but also gives app designers and developers yet another channel to raise revenue – not just from including ads in their apps, but from developing the ads themselves.
  • Ads can be built to have the same emotion as a television commercial with more interactivity than regular web ads.
  • Clicking on an ad launches the ad interface which act like apps themselves: interactive games, play audio/video, open a map, allow purchases, all from within the app
  • Users will be able to go back to the original app, right where they left off, with a single click.
  • Apple will own and sell all of the ads, and give developers 60% of the revenue.
  • All done via HTML5
• 1500+ more APIs giving developers more functionality to add to their apps
  • Calendar access
  • Video playback & capture
  • In-app SMS
  • Photo library access
  • Improvements to Map Kit
  • Quick Look application preview

OS 4 is available now for developers, will be available for iPhone/iPod touch users this summer and iPad users this fall. iPhone 3GS and 3rd gen iPod Touch devices will have full functionality, iPhone 3G and 2nd gen iPod Touch devices will have most of the functionality but no multi-tasking.

Props to Engadget and gdgt for the awesome live-blogging and picture streams!

Engadget – Live from Apple’s iPhone OS 4 event!

gdgt – Live iPhone OS 4.0 event coverage

* UPDATE – Apple just posted up video of the press event on their website.