Accelerate Downloads In Firefox
In this Ubuntu Video Tutorial I show you how easily accelerate downloads with an add-on for Firefox call Download Them All. It makes downloading linux distributions that don’t offer a bit-torrent tolerable. It will give you nearly the same speeds reliability of a bit-torrent without the need for seeders. Unfortunately it doesn’t work as well on lower bandwidth connections. The best part of the deal is you don’t have to pay a thing.
Tobias Mann
Ubuntu Video Tutorials 
That’s the best download addon for Firefox, but on my windows box i got FlashGet which installs a pretty good addon for itself which makes it much easier to download using it it’s kick ass fast too.
Interesting, I will have to check it out