More info - the NAS appears under "My Shows" - link to the Netgear forums with instructions and screenshots here:
http://www.readynas.com/?p=4324
Would be good if this could work on Virgin, not too bothered about the backing up, but if it could play other video's I've got saved on the NAS it would mean not having to turn the PS3 on.
In terms of archiving and the V+, don't forget that was output over SCART and so analogue. OK, this could be fed into a PC and digitised, but the quality wasn't / isn't great. Any archiving to NAS would be digital and so open to "manipulation". I suppose if they can get some kind of protection / DRM thing that means it will only play back on the TiVO it was recorded on, that would work.