I've just written a library called jsPDF (Give you the link below) which generates PDFs using Javascript alone. It's still very young, and I'll be adding features and bug fixes soon. Also got a few ideas for workarounds in browsers that do not support Data URIs. It's licensed under a liberal MIT license.
I came across this question before I started writing it and thought I'd come back and let you know :)
http://code.google.com/p/jspdf/
http://hayageek.com/generate-pdf-with-javascript/ //Try this link with step by step process