|pinkfloydeffect you can't link the three but you can use two adsl links in your pc.|
The ONLY way you can accomplish this without hardware that bonds the links physcially is to bring up a virtual machine in addition to your host.
You would never "split" a file between two interfaces.
You set your host to only use 1 dsl line. You set the VM to on the host to use the other.
Doing so would allow you to run firefox on one and IE on another.
Virtual pc is a free download and I believe VMware has one available also.