I couldn’t seem to find this in the Movable Type manual, but here’s the code that produces a Recent Comments list in the blog sidebar:
<div class="module">
<h2 class="module-header">Recent Comments</h2>
<div class="module-content">
<ul class="module-list">
<MTComments lastn="6" sort_order="descend">
<MTCommentEntry>
<li>
<a href="<MTEntryPermalink>#c<$MTCommentID
pad="1"$>"><$MTCommentAuthor$></a>
said “<$MTCommentBody remove_html="1"
trim_to="100"$>…”
</li>
</MTCommentEntry>
</MTComments>
</ul>
</div>
</div>