wxDownload Fast (also known as wxDFast) is an open source download manager. It is multi-platform and builds on Windows(2k,XP), Linux and Mac OS X(binary still not available). Besides that, it is a multi-threaded download manager. This means that it can split a file into several pieces and download the pieces simultaneously.
Here is another downloader, which can resume interrupted dloads, and which can be integrated with flashgot, in either firefox, or seamonkey.
However it requires the wxGtk libs to be installed. These can be downloaded from here, or this location.[/b] (3.8Mbytes)
To integrate with firefox/seamonkey download & install flashgot-0.7.7.xpi , then restart browser, select
Tools->Flashgot->More Options , then from the DownloadManager list, select "wxDownload Fast" . Then if you right-click a file link, then choose Flashgot Link, this will transfer the download to wxdfast.