Google has launched a music store and streaming service to rival Apple's iTunes, allowing customers to buy tracks directly from the Android Market.

Google Music lists more than 13 million tracks from labels such as Universal, Sony and EMI, and allows the saving of playlists online and the sharing of tracks with contacts through Google+.

The service also offers exclusive tracks from the Rolling Stones, Pearl Jam and Dave Matthews Band. Google has promised to court independent artists and smaller labels through the Artist Hub site.

"Google Music helps you spend more time listening to your collection and less time managing it," said a blog post by Andy Rubin, senior vice president of mobile at Google.

"We automatically sync your entire music library, purchases and uploads, across all your devices so you don't have to worry about cables, file transfers or running out of storage space."

Google Music could present the biggest challenge yet to iTunes. Apple has defeated all challengers to date, but Google has a huge brand and the resources to go head to head with the market leader.

It could also wean some people away from the Apple brand and convince them to move to Android.

Google Music is currently available in the US, and will be expanded to other territories soon.

Rumours over the past few months have swirled around the possibility of a streaming media service from Apple.

The speculation has picked up recently amid reports that the company is racing with Google to be the first with a streaming music and video service. But what will the service be called?

Silicon Valley blogger Om Malik may have an answer. He cites an unnamed source in reporting that Apple just purchased the rights to iCloud.com. The deal is not believed to have been cheap either, estimates pegging the domain's cost as high as $4.5m.

As Malik notes, the purchase doesn't necessarilly mean an imminent launch of iCloud, and Apple may have bought the domain for a future launch of a entirely different service.

Still, $4.5m is a lot of money for any company to spend on a domain name if they don't have very big plans for it.

There has long been talk of a secret project in Cupertino to offer a cloud-based version of iTunes. The system would reportedly allow users to remotely connect with a server and listen to their iTunes libraries without the need for an approved device or PC.

And it seems that Apple is not alone. Google is also believed to be working on a streaming music service of its own, and the rivals are working to get their service to the market first.

But according to Reuters, Apple is preparing to launch its music service, while Google's efforts are said to be stalling.

The launch of a cloud music service could only help Apple. The company currently dominates the downloaded music market and, even if a cloud platform was only marginally successful, at least the company is preserving its presence on the new platforms.

Apple posted updates for iOS, Safari and OS X last week, and now it seems that Windows users are also getting a reason to patch up their systems.

Apple has posted the iOS 10.2.2 release and security groups including US-Cert are advising users to update in order to shore up security vulnerabilities. Among the flaws addressed are vulnerabilities in WebKit which can lead to denial-of-service errors and possibly a remote code execution attack.

So, if you're using a Windows PC as your 'other' system, running a Windows partition on your Mac, or simply have friends and family that use an XP, Vista or Windows 7 system, make sure your copy of iTunes (and all other Apple products for Windows) are up to date.

Lots of reports are floating around about a new feature that could be coming to iTunes and MobileMe.

Apple is said to be working with the major music labels on a deal that would allow users to download their iTunes-purchased tracks on to multiple devices.

The deal would allow you to purchase and download a track on your iPhone and then re-download the same file to store and play on your home computer, personal laptop and iPod touch.

Such a possibility would make life easier for iTunes users and would make a lot of sense practically. After all, you don't have to buy separate CDs if you want to listen to a song on your home stereo and in your car. Why should users have to buy the song twice to use on two different devices?

Seemingly, the talks largely centre on how Apple will make sure that the songs are tied to one account and not simply passed around by multiple users.

These things are never easy to do, but hopefully we've reached the point where the record labels understand technology enough to green-light this sort of common-sense deal.