If you want to jump start your jQuery plugins, give this plugin framework a try: <a href="http://starter.pixelgraphics.us/" rel="nofollow">http://starter.pixelgraphics.us/</a>
Nice tut for simple plugins. For plugins that keep lots of state per element and allow subsequent modification thereof, I would suggest building with the jQuery UI widget framework. Among its conveniences are method calls via
$(element).customWidget('methodName')
I was pleasantly surprised to find the core to be completely independent of the template system, meaning there's no custom css mixed in there, and no explicit/hacky support for any of the jQuery UI widgets.