I need to build a page that looks like Mac Mail or an Outlook Inbox. where the one page has a top panel and a bottom panel, and there is a divider in between that you can use to
There are a few jQuery plugins that can do something like this. I think this jQuery Splitter plugin is what you are looking for though.
jQuery UI offers this as a plugin. Very simple and it really works well. I always use it. Here is the link with instructions:
http://docs.jquery.com/UI/Resizable