Multiget

MultiGet (http://multiget.sourceforge.net) is an easy-to-use and open source file downloader for Windows / Linux / Mac OS X / BSDs.
The new MULTIGET offers you even faster downloads by multi-thread-and-server-downloads and a download tool for downloading from friends: RetoShare.
Mutliget file downloader is programmed in C++ and has a Graphic-User-Interface (GUI) based on wxWidgets.
It supports HTTP/FTP protocols which covers the requirements of most users.
It supports multi-task with multi-thread on multi-server.
It supports resuming downloads if the Web server supports it, and if you like, you can reconfigure the thread number without stopping the current task. It's also support SOCKS 4,4a,5 proxy, ftp proxy, http proxy.
A new feature, that is called P2SP, or in other words, get file from multiple servers, and combine the data from different sites into one file! This makes downloads complete much faster than all the most other download tools.
Tested on many system such as : Windows 2000, ubuntu ,kubuntu, xubuntu, fc5, opensuse10.4, mandriva 2007, MEPIS 6.0, PCLinuxOS, CentOS4.4, Puppy2.0, Xandros, edubuntu, RedFlag workstation 5, MagicLinux, dubuntu, archlinux, Hiweed, FreeBSD, MacOS etc. It can only depends on GTK+ runtime environment in Linux if statically linked with wxWidgets.

SuSE users:
Download multiget for SuSE (look for Gecko ;-) ) from http://multiget.sourceforge.net
Extract to a folder, you will see only one file, double click on it, that's it! It runs!!

Screenshots: