Also there are several methods to approve new members without using the approval queue.
For registrations:
Enable Email Verification?
Require a Unique Email per Account?
CAPTCHA verification?
Set the new members group to a new group that has limited powers(no pm,only replies to posts no shout box,etc) and or moderated posts that mods can approve. And auto promote them to the regular group after x number of posts.
Also you can automate stop forum spam:
Auto with Message
Auto with Silent Fail
All that without reverting to manually approving new registrations via the registration queue.