Best practices for JQuery namespaces + general purpose utility functions

For jQuery plugins and such the pattern is to use $.fn.myPlugin if you want it to be available on elements, and $.whatever if you just want to use the namespace. I recommend reading the official Plugins Authoring document and these articles.

But jQuery aside, the easiest way to namespace your utils would be along these lines:

var utils = window.utils || {};
utils.method = function(){};

The basics of namespacing in JS hasn't really changed lately - You should check out snook's article, DED's elegant approach and this SO question.

The main advantage of using a self-invoked function to declare namespaces is you can execute stuff privately before returning the object. Also, the object will be ready for auto-complete by your console, which you'll miss on the $ namespace because jQuery returns a function rather than an object.