Launcher icons are stored in /usr/share/applications. Go to your terminal and type: sudo nautilus /usr/share/applications, then right click the application you want, select Properties and click the icon on the properties window. Now you can set it to any icon you want.

*edits

*here is an example .desktop file.

[Desktop Entry]   

Name=Give me a name!    

Comment=Explain me here!    

Icon=/home/t32/t32.png   

Exec=/home/t32/bin/pc_linux/t32marm -c /home/t32/config_usb.t32   

Terminal=false   

Type=Application   

Categories=This is important, select a category that is present  

StartupNotify=true   

*use one of the following as category: Accessibility, Customization, Education, Games,
Internet, Office, System, Accessories, Developer, Graphics, Media, Other. Exec is the command to run, Icon is an absolute path to where the icon lives. Usually you wouldn't need to alter anything else. You may keep this as a scratch and reuse.

*copy this to a whatever-you-name.desktop file, edit as needed and put the file in the /usr/share/applications directory. If paths are true, it will pop up in the gnome menu. I don't know if lucid had Unity or gnome3, but if it has, when you search it by the name you gave it, it will be visible in the unity lens, gnome activities thing. If you have gnome2, it would be grouped under the corresponding category in the applications menu.

*And this kind of launcher are so cute that they are valid in GNOME, KDE and (probably) all others.