By Margaret Lyons
April 08, 2010 at 07:38 PM EDT

Steve Jobs unveiled OS4 for the iPhone and the iPod Touch today, and the big news is multitasking. Hell to the yes. Finally, you can stream Pandora in the background while using other apps. Hotcha! The updated OS will be available this summer for 3GS phones and third-gen iPod Touches, but older models won’t be able to run the full system — and it won’t be available on the iPad until fall.

The other “tentpole” features of OS4 are folders, which will allow you to organize apps; “enhanced mail” improvements to the native mail app; iBooks for the iPhone, which is major, considering how many e-books iPad users have bought already; better development options for business apps; social gaming; and iAds — in-app interactive mobile advertising.

It’s a major improvement for the OS, but I can’t help but think that the real news here is iAd. Most online advertising is search-based, but people don’t use search as much on their phones, so there hasn’t been a dominant form of ads yet on mobile devices. Apple’s planting one hell of a flag in that department right now.

What features were you hoping for, PopWatchers?