You can create Gantt charts on the wiki using an XML based project plan description. Instructions are here: http://www.logilab.org/projects/pygantt/documentation
<project xmlns:pg="http://www.logilab.org/namespaces/pygantt_docbook" id="myprojet">
<label>Cytoscape</label>
<task id="module">
<label>Cytoscape v2.2</label>
<task id="codeFreeze2.2">
<label>Code freeze</label>
<duration unit=weeks>4</duration>
<constraint type=begin-at-date>2005/08/15</constraint>
</task>
</task>
</project>