Oh god... Dazzle...
http://www.martialwave.com/images/easycap.jpg
This is what i use, it produces HD videos, from any console, and it only costs around 10 bucks... Though you might have to buy a jack splitter.
I use an HDMI, though. I know it's hard to tell from the camera... :P
Well, I suppose Youtube wouldn't show much difference between that and HDMI. Like you said, though, I would have to get a jack splitter.
So you bought it from that site?
Edit:...Wait
"Sample Order - £14.99 inc. VAT and P&P
(UK ONLY)"