How good are these "powerline" adapters?

[pieman109]

Quite interested in these things, would make networking a lot easier. Do they work with a "DSL" connection, are they easy to set up, how reliable are they, do they work with "Vista 32bit", and lastly is they any interference from the mains voltage?
Cheers.

 

[pieman109]

Cheers guys, theres some really useful info here. I must admit when I first saw these things advertised, I thought it was joke!
I fancy trying a pair of these out with the option to put more pcs onto a home network.