How to bond two dsl lines - one internet connection

You need a load balancing router with two WAN inputs.

You've never set one up, have you?

For instance, using a Netgear Prosafe firewall you can use 2 seperate lines. The best you can hope for is load balancing (eg: smtp on one, web on another) or failover. You cannot "shotgun" the 2 lines.

A sonicwall will give you similar functionality.

You cannot "bond" the 2 lines in the manner you are eluding to.

True, you cannot actually bond two ADSL lines, but what most people really want is to automatically use both lines, and a load balancing router will do that seamlessly. . .