MultiGet is an easy-to-use GUI download manager for ubuntu .It is Look and work like famous windows download manager flashget.
It supports resuming downloads, It supports HTTP/FTP protocols . It supports multi-task with multi-thread on multi-server. You can reconfigure the thread number without stopping the current task.
MultiGet runs natively on Linux, and it supports multiple operating system too. It was tested on many system such as : Windows XP, ubuntu ,kubuntu, xubuntu, Fedora, opensuse, mandriva, MEPIS , PCLinuxOS, CentOS, Puppy, FreeBSD, MacOS etc.
MultiGet is available from Ubuntu universe respository
Howto Install in Ubuntu
$ sudo apt-get install multiget
or you can use Synaptic Package Manager