Originally posted by: JackMDS
Combining Bandwidth -
http://www.ezlan.net/loadbalance.html
To get a jump start on what you'll find at Jack's link, your ISP and current task need to support load balancing. That said, if your app and support multiple connections, then you could theoretically pull this off for SEPERATE files.
theoretically, if you can get an app to pull off this you could theoretically download weirdjapanpor.rar.tgz.32 and weirdjapanpor.rar.tgz.33 using different pipes.
otherwise it would have to be a conscious decision on your part to initiate half and half downloads (using DNS trickery perhaps)
It really depends on the app and the router you will be using.
Pfsense should be a good place to start btw as I believe they went farther with dual wan (failover and aggregating) than Manuel did...