The Specialist has released a tool that allows Xbox 360 owners to use HDDs that are not certified by Microsoft. That means you'll be able to use your SATA HDDs with your Xbox 360s (insert "yay!"s and riotous joy).

There are still a few limits, though. For now, the tool only works with the Western Digital BEVS series and you can only use a 20GB drive. Still, this'lll save you quite a bit of cash if you go this route instead of buying a standard 20GB hard drive for your Xbox 360. The Specialist also says that once biggere Microsoft-certified HDDs come out, you'll also be able to use bigger HDDs with his tool.

For the technically-inclined, here's a look at how it works, straight from the Specialist:

x360 HDD's contain information on sector 16 about the HDD: the HDD serial number, the model, the firmware version and the size in sectors is stored here. The x360 asks the HDD to identify itself, by sending an 'IDENTIFY DEVICE' ATA to the HDD. It will compare the returned information to the info that is stored on sector 16.

This information on sector 16 is signed and thus can not be changed. This tool will mod the FW from the WD HDD to comply with the information on sector 16, so that the 'identify' information will match the information on sector 16 and your x360 will accept the HDD as valid.

Remember, read the readme file included in the download before you use this. It contains usage instructions as well as a short FAQ.