It is, of course, completely compatible with other routers.
Ufortunately the user name is the MAC address of the router with @sky.com on the end and the password appears to be generated from the MAC address.
Once you have their router you can extract the login details (there is a hack to do this) at which point you can use any router.
Unfortunately before you get the router there isnt much you can do.
I am wondering if SKY actually log the MAC address of all the routers they send out or whether someone elses login would work on your line ...