Well, I'm looking to direct internet traffic between different applications through different network adapters. How would I go about doing it?

Ex: Firefox takes the route of Network Adapter 1, and MSN Messenger takes the route of Network Adapter 2.

You may want to look into the "route" command. With it, you may be able to direct traffic to certain destinations to go through a certain interface. I'm not completely sure that will do what you need, as the "route" command is not something that I mess with much.

If you want a little bit easier approach, then just use Virtual PC. You can choose which network adapter you want each virtual machine to use.

Route = No
VPC = Yes

Me wonders what is the point of this exercise?