Steve Jobs lit up a packed crowd at the World Wide Developer's conference in San Francisco today. The Apple CEO's presentation introduced some interesting updates to Apple's computer and mobile operating systems. But most intriguingly, he unveiled the company's hotly-anticipated iCloud service, which syncs users' music, photos, e-mail messages and backup data across every device (iPhone, iPad, MacBook etc). Here are the highlights from Jobs's presentation:

iCloud

As Jobs put it today, "iCloud stores your content in the cloud and wirelessly pushes it to all your devices. It automatically uploads it, stores it, and pushes it." That includes photos, books, calendar information, videos and even the page numbers of the latest documents your reading on your iPhone or iPad. The basic cost to the user for all of this service snycing is nothing, which garnered a lot of applause at the conference. "There will be no advertising (contrary to previous rumors), and calendar, mail, and contact sync is free (for up to five gigs of mail)," writes Engadget's Joseph Flatley. "Also in store is the new PhotoStream cloud feature, which is essentially a gallery in Photos that exists on all of your iOS devices, Apple TV, your OS X and even your Windows PCs, and syncs through the cloud." As for your existing music library, iTunes will match your music to the cloud server for a fee: $25 per year for 5,000 songs. "Will this work with massive amounts of pirated music?" wonders Gizmodo's Sam Biddle. "We don't see how it couldn't. So whether you've amassed a giant library from CDs or the seedier corners of the internet, Apple's giving you unlimited access for 25 bucks a year. Someone at the RIAA just punched a hole in the wall."

OS X Lion

Lion offers a number of interesting new features. One of them is Mission Control, which is basically a better version of Exposé. This integrates the Dock, Dashboard and icons of open programs into one place. "Flinging windows to different spaces also just got a whole lot easier, as Lion will let you drag whatever you're working with into sortable stacks in the top-right corner," writes Gizmodo's Sam Biddle. Lion also offers the Launchpad, which organizes your programs in a way similar to how the iPad organizes apps. The new Resume feature guarantees that when you quit a program and restart it later, it appears exactly how you left it down to the most detailed aspects like highlighted text on a page. Lion also comes with an updated Mail app, with multiple ways of viewing your message: fullscreen, three column and a conversation view of your letters. They've also improved Mail's search functionality. "On the productivity side of the equation," writes Nicholas Kolakowski at eWeek,  "Lion includes Auto Save and Versions. The latter is Time Machine for individual documents, allowing the user to revert to any number of previous versions with a single click. AirDrop wirelessly shoots files to other users, and FileVault keeps information secure with XTS-AES 128 data encryption—for both internal and external drives."

iOS 5

The latest installment of Apple's mobile operating system introduced Apple fans to a number of very cool apps. One of the most loudly-applauded apps was Notifications. "OS 5 introduces something Apple calls Notification Center, a single place that combines all of your notifications," writes Lex Friedman at MacWorld. "You can access Notification Center at any time with a single swipe down from the menu at the top of your device--a gesture which, it must be said, achieves the same effect already on Android phones." Another feature of iOS, the phones can now be synced over the air--no more USB cables. The Safari browser app gained some new features. "Like the similar functionality in the desktop version of Safari, Reader lets you get (and share) all the content of an article, removing navigation, ads, and other content--leaving only the text," writes Friedman. To many, the Reader feature will be viewed as an InstaPaper killer. iOS 5 will also have greater integration with Twitter: "Several of Apple's own apps, like Camera Photos, Safari, YouTube, and Maps will all support direct Twitter integration, so that you can quickly post data from those apps to your Twitter account," writes Friedman.