steekR DriveDrive is a free application for Windows that, using the web service offered by steekR, offers you 1GB of extra online disk space that you can integrate with your PC so that you can use the space as though it were local.
You can access the disk through My Computer like you would with any other drive. The only difference is load time, since if you want to use one of the files you've stored online, you'll naturally have to download it first.
All of these details make steekR DriveDrive a simple and useful tool that is sure to surprise you.
Requires free registration on the creator's website.