Mudim Vietnamese Typing is a simple and easy custumized plugin for Joomla 1.5. You can change some parameters in plugin management section.
You can type Vietnamese in Frontend and Backend.
See at Mudim's homepage for more details: http://code.google.com/p/mudim/wiki/MudimAPI
Demo: see this webite at the TOP/BOTTOM, press F8 for show/hide this form, F9 for turn on/off Vietnamese typing.
2008-06-15: use event onAfterRoute, fixed pdf display.