The new DiscussIt Plugin for WordPress (v1.5) has lots of new features including:
(without annoying captchas!)
New moderation types
As well as improvements to the admin interface.
As well as adding robust spam-protection for your WordPress blog, the new DiscussIt plugin now supports two different moderation types:
Post-Moderation shows unapproved comments on the blog before they’ve been moderated. and Pre-Moderation hides comments until they’ve been moderated.
For more details see the DiscussIt WordPress Plugin page.