Google Blogoscoped points to Online TV Recorder. It's a service which works like a PVR but you don't need any special hardware. Online TV Recorder will record the show for you and then allow you to download the programme.
I do wonder whether this is legal. It's certainly legal, in the UK, to record a television programme from the television and keep it for up to 30 days (or something along those lines, IANAL). I believe that it is also legal to go around someone else's house and to record a television show on their VCR and then take it home to watch.
Following that line of reasoning, this service should be legal as this service basically allows you to do that but uses the internet as a distribution medium.
However, from the other point of view, it is illegal to download a television show from BitTorrent. This service basically allows you to do that – download a television show but the difference is you have to let them know your going to download the programme in advance.