Prompted by this blog post at Mootus.com, here is a link to Harvard's site for free legal research resources.
In our field, there is the Freivogel on Conflicts site, which is indispensible when you want to know what's new in conflicts or want to research particular scenarios. (Thanks, BIll.)
[update] Zimmerman's Research Guide has a legal ethics page.
ABA site.
What other free resources are out there for us in particular?