Aaron is an interactive business analyst, information architect, and project manager who has been using Linux since the days of Caldera. A KDE and Android fanboy, he'll sit down and install anything at any time, just to see if he can make it work. He has a special interest in integration of Linux desktops with other systems, such as Android, small business applications and webapps, and even paper.
In your Gmail, all you have to do is to enter the term size:10mb in the search box and all emails larger than 10MB will show up in the list. You can change the number to reflect the size you want to filter.
This is so far the easiest way to filter your emails by size.