Just got adsl installed today, still got my Virgin line running too, would be very interested to know how you setup both to run on the same computer/network.
I have 2 connections on 1 pc using dual lan ports on my mobo.
In vista you can go into the LAN connection properties IPv4 properties then advanced and set the Interface Metric for each connection, lower numbers are higher priority.
I have O2 - Priority 1
VM - Priority 2
So now all traffic goes via the O2 unless I set a static route to tell it otherwise.
Setting up static routes...
Run CMD prompt as admin and static routes look like this...
route -p add <IP you want to route> MASK 255.255.255.255 <Default gateway of router>
So say for i want to add a static route for google, ping google.co.uk to get ip which is 216.239.59.104, then say my VM gateway is 192.168.1.1 the route would be like this
route -p add 216.239.59.104 MASK 255.255.255.255 192.168.1.1
If you want to add all IP's in that range then do it like this
route -p add 216.239.59.0 MASK 255.255.255.0 192.168.1.1
You can add as many static routes as you like.
Hope that helps.