Unlike other file storage/sharing services, Wuala doesn't provide you with web space. Rather, your files are encrypted and then stored on the computers of other Wuala users. While this might sound a bit scary, the upshot is that you can store large amounts of data. The more space you allocate for Wuala on your hard drive, the more online space you can access. And your files are duplicated on multiple computers so that you shouldn't have problems accessing your files even if some of the folks in your network have turned their machines off for the night.
Wuala has a desktop client for Windows, Mac, and Linux that you can use to upload and download files. Or you can access a web interface. The service is still in beta, so nobody's promising that all the kinks have been worked out. But as of today, Wuala is in public beta, not private.
