cFosSpeed is a High-Speed-DSL Driver, which enables you to prioritize your simultaneous connections to the Internet.
Technically is the program a Protocol- and Application based QoS. The Manufacturer of cFosSpeed call it Traffic-Shaping.

I use cFosSpeed myself since over a year now, and I'm very pleased. There are two versions for use with and without Routers.

The changes of the new Version are primarily about Windows Vista Support.
A x64 Version is now available, too.

Downloads:
cfosspeed-v313-build1225.exe
cfosspeed-x64-v313-build1225.exe