What would one be getting one's self into if one were to volunteer to
take over the moderation duties?

Two things. One is the technical aspects of hosting a moderation
server. There are people who do this (for multiple moderated groups),
and are likely to offer their server, in a setup which would let you
do the actual moderating via a web interface of some kind.

Second is approving each message. This involves checking frequently,
if moderation delays are to be minimized. For this and other reasons
it is desirable to have a moderation team, rather than a single person.

Oh, and there is the question of whether the existing moderator is
willing to transfer things over. If the answer is "no", there isn't
much which can be done, sadly, but in most cases of a semi-absent
moderator, they are glad to be rid of the duty.

For more information, consult for example:
http://www.big-8.org/dokuwiki/doku.p...aqs:moderation