If your Internet connection is slow or prone to interruption, using a download manager can save you a lot of time and trouble. The best download managers can pause and resume downloads, download multiple files at once and download files using alternate protocols such as FTP and BitTorrent.
They also support downloading of Flash video files from sites like YouTube and Google Videos. The following download managers are among the best there are, and all of them are totally free.
Free Download Manager : http://goo.gl/pbjO
Download Accelerator Plus : http://goo.gl/5W79n
GetGo Download Manager : http://goo.gl/vgw3w