There are a number of ways to do this and your options are only limited by your imagination . . . and, well, the MT tags. First, this will only work in MT 2.0+ so go upgrade right now if you haven't!
If you want to list recent comments in moveable type, you have two choices more or less:
1) You can list a specific number of recent comments in which the output will display ALL these comments regardless of whether they are all for the same entry.
2) You can list a specific number of recently commented upon ENTRIES and list the LATEST comment in that entry. The difference here is if someone makes 3 comments on one entry, only the most recent will show up.
I encourage you to PLAY with these to find what suits your needs best and look through the MT manual to explore your tags options. What I list is just an EXAMPLE of what you could do, to get you started in the right direction. I'm sure this is not the only two ways to do this, so play with the tags and have fun!
Method One:
Listing "x" number of recent comments.
<MTComments lastn="5">
<$MTCommentAuthorLink spam_protect="1"$>: <$MTCommentBody remove_html="1" trim_to="100"$>… [<a href="<$MTBlogArchiveURL$><$MTCommentEntryID pad="1"$>.php#<MTCommentID>">go</a>]<br/><br/>
</MTComments>
Method Two:
Listing "x" number of recently commented on entries with the last comment per entry.