The jQuery site lists the basic plugin syntax for jQuery as this:
(function( $ ){ $.fn.myPlugin = function() { // there\'s no need to do $(th
To find a clear explanation of this and other modern javascript tricks and common practices, I recommend reading Javascript Garden.
http://bonsaiden.github.com/JavaScript-Garden/
It's especially useful, because many of these patterns are widely used in many libraries but not really explained.