DECORATE Assistant is a tool to help people write their own DECORATE actors for ZDoom/Skulltag. The application simply pastes code for action functions and actor flags with the parameters ready to be changed. All you have to do is right click the application in the system tray, select the function you wish to use and change the parameters (if there are any). It is designed to help people enter code without having to browse the wiki all the time for reference.
More details and download here (dead link: file not found)