I think the key point here is on the amazon page..
"All linksys broadband routers, unless otherwise stated, connect directly to an ETHERNET broadband connection. This is standard on all Telewest and NTL broadband services, but to use with ADSL you will need a modem with an ETHERNET port."
I use a
Linksys Wireless-G Router at home connecting to a ntl cable modem which has an ethernet output, it works great connecting to 2 pc's, my work laptop and a Dell X30 pda, it really was plug and play.
If your ADSL modem has an ethernet port that connects to your PC then the Linksys kit will work fine, maybe consider going up a couple of quid to the unit I have linked to, it is .g compatible which whilst it will not affect browsing speed it will make file transfers between the PC's noticeably quicker. Sorry cannot help on the Mac side of things.
g'luck...
