<p>Our team is experienced in web development (tomcat/Oracle) but not with AJAX on our existing projects.  This is new technology for us, so I want to introduce this carefully and correctly.</p>

<p>What should I look at in terms of frameworks or best practice or common pitfalls?</p>

read this:
progressive enhancement
and use a library such as
jQuery
,
mootools
, or
YUI
it'll save you many headaches with cross-browser implementation.
this
will show you why you want to use a library.