Do people that use the word "kudos" ever amount to anything?
http://josh.com/teepipe/index.htm
Q: Don't I need some support from my ISP(s) to recombine my traffic coming off these multiple links?
No, as far as your ISP(s) are concerned, you are just a normal user. You don't need anything from them except a standard connection.
TeePipe Home includes an HTTP proxy that runs on your local machine. It intercepts the requests that your browser makes and automatically distributes them across the available links. Since each page you see on your screen is typically composed of many HTTP requests, this works quite well.
For FTP requests, the proxy can split the requested file into "chunks" and distribute the downloading of the chunks across the links.
For web pages that do not include any other HTTP requests (no images, no frames, no flash), there will be no speed improvement because the page can only go over one link. Luckily (unluckily?) there are not any pages like this left on the internet. :)
Note that the absolute best possible solution would be if you could distribute the traffic byte-by-byte across the available connections, rather than only load balancing HTTP requests. To do this, you would need something at the head end to recombine the streams together. There just happens to be a*perfect* system that already does exactly this. It is called Google Web Accelerator. If Google would only publish an API for this product (or even just tell me that they don't mind if I hack it), then TeePipe Home would be able to perfectly use all the bandwidth you've got. So, if you know anyone who works in the Google Web Accelerator department, please urge them to get in touch with me!