Ok there are no exact ports for your dsl per say.. but there are normal or default ports that WinMx uses ....
Those are TCP 6699 and 6257 UDP.
Your 2 wire box will need to have the ports forwarded to allow WinMx to work as a primary. If you want to run both as primary you will need to assign a different set of ports to the second machine. Adding a 1 to both should work like 16699 and 16257.
That said the way to forward the ports is to find your instructions for the 2wirehttp://www.portforward.com/routers.htm
There you need to look up your model and follow the instructions. Each computer will have its own Internal IP address that will help the 2wire to know which computer to send the data to and on what ports.
Here is how you can find the ips of the computers:
Start > Programs > Accessories > Command/MSDos prompt.
In the black DOS box type in ipconfig
for getting the ip of one machine.
Be sure you set four rules.. one for each port and each machine.
Once this is done make sure you also have access allowed in any XP firewalls and other software firewalls you use. Also in Norton Worm Protection if you use that as well.
Dont forget to also go into WinMx Settings > Incoming TCP and change that to the top option 'Listen on port (insert port here 6699 or 16699)
Then go to IN/OUT UDP and change that to the top option 'Send and receive on port (Insert port here 6257 or 16257)
Then just let me know if you have any other questions or problems.