Apple's latest version of their operating system, Mac OS X 10.6 (Snow Leopard), goes on sale this Friday. As its name suggests, Snow Leopard is a refinement of its previous Leopard 10.5 OS, offering performance and functionality improvements. Apple has made upgrading from Leopard a snap and cheap too, with an upgrade version costing only $29 for Intel-based Macs running Leopard.

Upgrading from Leopard to Snow Leopard is really easy and Apple lets you choose what type of upgrade to do: a clean install, an archive and install, or an in-place upgrade. A clean install wipes away all your data and installs a clean version of 10.6. Archive and install saves all of your personal data (not applications) and puts them into a folder that you can access in Snow Leopard. An in-place upgrade, which we don't recommend, will save all of your applications and data and just upgrades from Leopard. This isn't recommended because it may cause incompatibilities and issues further down the road. If you are using Tiger, you must perform a clean install and Snow Leopard will only run on Intel-based Macs. Snow Leopard also uses 7GB less space than Leopard, which means you'll gain all that space back after you upgrade.

As with some operating system upgrades, you'll get a new user interface that you have to relearn, but not with Snow Leopard because it keeps Leopard's already well-designed interface. You will, however, notice smaller interface tweaks and new dialogs with continued use of Snow Leopard. But one thing you will notice for sure is the performance boost with 10.6. Running on both new and upgraded Macs, you will see a noticeable increase in speed, including start up and shut down times. This is due to the way that Snow Leopard's architecture was rewritten to take advantage of 64-bit CPUs with multiple cores. The new technology built into 10.6 is called Grand Central Dispatch (GCD), which Apple says uses modern Intel CPU's abilities to perform multiple tasks using all available cores. GCD automatically manages the various "threads" that comprise each task that must be performed by the CPU and no longer relies on software developers to write their applications to do this themselves. The entire 10.6 system has been written in 64-bit to take full advantage of this.

Finder, the file browsing system, has been rewritten using the new, more efficient Cocoa programming language. The interface is still the same, but with a few minor tweaks here and there. The icon view now lets you choose icon sizes of up to 512x512-pixels and the default icon view now shows live previews of video or multipage documents. The eject functionality of Finder has been upgraded to now show you what programs are using an external disk, camera, or network drive that is preventing you from ejecting it instead of an error message just telling you it is "in use." It also no longer bugs users about improperly ejecting a drive even if you did remove it safely.

A nice feature that Preview has gotten in Snow Leopard is the ability to intelligently select columns of text. With past versions of Preview, selecting text in a column would select the whole row of text across the whole document and not down the one column. Preview in OS 10.6 now looks the document to see where the natural flow of the document is and selects text based on that.

Safari has also been rewritten and because of that, it loads Web pages even quicker than before and JavaScript-intense pages load in a snap. Apple claims Safari is up to 50% faster and is crash-resistant because it now runs plug-ins separately from the browser.

Exposé, which was introduced in 10.3, shows smaller windows of open applications to get a peek at all open windows across all applications that are open. The new Exposé shows these windows in a more grid-like fashion and also lets you selectively see open windows for a specific applications by just clicking and holding the applications icon in the Dock.

Stacks, which allows for easy access to applications, documents, and more right from the Dock has also been improved. If a pop-up stack is too large to be displayed all at once, a new scroll feature is enabled to let you scroll through all the available items.

QuickTime X is the new version that is included in Snow Leopard and it has a new cleaner interface with video editing features built right in. There's also been upgrades to media playback, including live streaming, and also features that allow direct upload to MobileMe and YouTube.

iChat features a minor upgrade that allows for 640x480 video chats and a feature that uses AIM relay servers to establish a video chat connection even when a direct connection doesn't work. This might be a huge feature for those who use iChat a lot for video because this is a common problem.

Snow Leopard also will automatically search for printer drivers over the Internet when you plug in a new printer. It also will periodically check for new drivers and download them via Software Update. Another handy, yet minor feature, is the ability to use Core Location technology to automatically set your time zone information for you. It does this by looking for known Wi-Fi hotspots and setting the time accordingly. This is handy for frequent travelers and people on-the-go.

A really innovative feature is Snow Leopard is the ability to draw Chinese characters using the multi-touch trackpad built-into a Mac notebook. As you draw them, the computer will automatically suggest characters based on what you are drawing and help predict what you are typing.