I have tried and failed to create to find any good tutorials on writting plugins for Eclipse and the closest I have assumed a large degree of knowledge about the internals of Eclipse.
For what it is worth I have the programming skills to write the plugin. I need help with getting it plugged into Eclipse correctly.
Maybe this could be an interesting site for you:
http://www.eclipsepluginsite.com/
It covers setting up your plugin to advanced plugin tutorials.
I personally use it all the time.