I downloaded a copy, dropped some files onto it, but couldn't get it to work very well during my tests. The requirements say Mac OS X Tiger and up, but it was no go on my 10.4 G4. Some users over at MacRumors had better luck than I did.
The beta is limited to 10MB files but according to the developers it will shortly expand up to 100MB. I look forward to when they get this up and working. It looks like a nice alternative to yousendit.