While Microsoft's 250GB Xbox 360 hard disk is currently only available in North America as part of a console bundle, according to a new ad popping up on the 360 dashboard, that's about to change.

This "Make More Room for Entertainment" advertisement popped up on the Xbox 360 dashboard today, urging console owners to head to a participating retailer and pick up a brand new standalone 250GB hard drive, complete with transfer cable for securing your data during the upgrade.

Unfortunately none of the retailers I've checked - GameStop, Amazon, or Best Buy - are currently participating, and the Xbox.com accessories page doesn't have a listing for the drive by itself. Still, that's definitely an advertisement for the drive, so I'd expect the lack of availability to be rectified shortly.

Since there are no retail listings for the drive, we still don't know how much it will cost. The Japanese version is currently available for import at Play-Asia for $160, and the 120GB hard drive Microsoft sells in the states sells for $129.99, so one might expect a reasonable price somewhere in that range. We'll let you know once we know for certain.

Thanks to Taylor for pointing out the ad!

Update: And we have a price! $129.99 for 250GB, the same price the 120GB was going for previously. Not a bad deal, all things considered.