I was downloading Ubuntu Studio the other day and being 1.4Gb I left it downloading while I went off for the day. However, when I returned I saw the download had stopped at 58%!
Not wanting to waste time, bandwidth and money downloading it again I did a little search and found out about ‘wget‘. It contains a command to resume incomplete downloads. So I only had to open the terminal in the folder where the file is contained and enter the following “wget -c http://cdimage.ubuntu.com/ubuntustudio/releases/9.10/release/ubuntustudio-9.10-alternate-i386.iso“
The ‘ -c ‘ is the command used to continue a download and as long as you open the terminal from the folder containing the file, wget will continue the download from where it originally finished.

FOSS 4ever!
The page I found this on is http://www.cyberciti.biz/tips/wget-resume-broken-download.html