Beating to it as getting a link from what I bought on amazon the other day so the BT home hub can be plugged into computer in another room on the new BT infinity, Kit not where I wanted and this the easiest way. Read they never do the full speed but at 37Mbs internet conection ok.
Then plug the 1 output it gives to the old router as a 3 way switch for the telly, blueray player and freeview recorder that all have ethernet connections and works ok.
I could not get the CD software to work for the encription set up but what I got on the link have a manual set up botton and the led flashes a certain way to know what is going on, did not work on windows 7 but says it does.
also read they need to be on the same circuit as wont get past the electricity meter, maybe not the new posh digital ones but my old black spinning wheel thing it does as could connect next door downstairs, 1 incoming cable for the 2 flats that splits to our own meter and fuse box (of course). So make sure encription is set so no one else gets on your network or internet.
It works for me for BT infinity kit and my old netgear router.