I just installed Matlab under linux and realised that it does not come with a proper icon. So I sat down and played around with Inkscape for a while to make a high quality vector graphic from the classic Matlab logo. It's not completely the same, but I think it's reasonably close. For a desktop Icon it should be sufficient.
To create a desktop shortcut for Matlab in Ubuntu Linux, right click on the desktop and select "Create Launcher...". In the command field enter the path of your Matlab binary, e.g. "/home/Applications/MatlabR2008b/bin/matlab". You can then click on the icon with the spring to select another icon.
Find the Matlab svg icon here.
Btw. you can get the Matlab logo plotted as a function if you type "logo" in the command promt.
