[jQuery] Applying JQuery from an existing node?

[macon]

Is there a way to apply JQuery from an existing DOM element?

For example I have a checkbox element with an onclick handler that
calls a function like this:

<input type="checkbox" onclick="doSomething(this);"/>

In the doSomething(thisNode) function I want to apply JQuery to the
thisNode argument rather than locate the element again using JQuery.
Something like:

$(thisNode).parent.css("color", "red")

Thanks,
Matt

(ps I'm quite new to JQuery so sorry if this a bit of a noob question)