JQuery TextArea AutoGrow Plugin

Elastic is a very good one, and it handles CTRL + V cases too.

You can visit the website and try out a demo.

Why not use it?? http://plugins.jquery.com/project/autogrowtextarea

Or another updated version of this plugin here: https://github.com/ro31337/jquery.ns-autogrow

This is the one I ended up using. Working great so far!

http://www.jacklmoore.com/autosize/

The JQuery Elastic plugin is slow and didn't work for me in IE8.