chocojon invited me to Joost - I think anyone can now get invited, so let me know if you're interested. After an initial networking problem (no idea what the cause was, but restarting both the gateway firewall and the local machine's firewall seemed to solve it) I was able to get picture. It can stutter a little for the first 20 seconds, but after that it's really pretty solid. The programmes all appear to be in 4:3 format at present. Would be nice to see a widescreen option/programmes. On our 4Mb cable broadband, the sound and picture quality is pretty much the same as SD cable tv channels - i.e. perfectly serviceable. I haven't yet worked out how much bandwidth it consumes to try to ensure I keep us from getting throttled.
What Pandora did for music, Joost is doing for telly - although Joost is (will be?) advert supported and shows whole series, Pandora only allows you to choose music similar to one you specify.
There is a channel on there called 'Gong', which seems to have 4 or 5 anime series. :) The range isn't spectacular at present - enough for most people to find something they like, but I'm hearing they're doing deals with big companies keen to ensure they don't turn out like the RIAA.