Pogoplug is not a free service. I bought one thinking it was. They actually cap the amount of data you can store. I believe it is 5GB for free.
Mine's running Arch Linux Arm now, with Open VPN, NFS, Samba and simple DLNA. Much more useful! I just wish I could re-encode the stream to my iPad. Often the video on my iPad refuses to playback proper.
I had the Sheeva, and I now have the Dreamplug. I wish someone would bring one of these to market with USB3 and still have the dual-GigE's.
[1]: http://pogoplug.com/devices