No need to wait for the 27th. SkyDrive for Windows can be downloaded and installed now. The app appears to transfer a full copy of your SkyDrive folder to your local hard drive and then sync changes to the cloud, so make sure you have those maximum of 25 GB available.
It also promises to make your files available from other computers, though the mechanism is not clear yet.
The app features:
Also current SkyDrive users are provided with an option for a free upgrade to 25Gb storage. So, go to skydrive.live.com/ManageStorage and grab your free upgrade.
SkyDrive for Windows can be found here.
Thanks Alessandro for the tip.