I wish I could report that SmalltalkDoc is done and ready to use, but unfortunately it isn't a priority item; Mark Roberts and I do what we can with the (very) limited resources available to us. In case you missed the presentation we did at the last Smalltalk Solutions conference, SmalltalkDoc is intended to be a comprehensive facility for documenting Smalltalk components: tools for editing and storing documentation, tools for indexing, cross-referencing and searching documentation, and web-based tools for browsing it -- all based on XML.
At this point, only a preview version of the SmalltalkDoc editing tool is available; loading it adds a new tool to the Refactoring Browser. Select a component in the browser's navigation panes, click on the new Documentation tab, and the browser's tool pane shows the documentation available for that component, which you can then edit to your heart's content.
As far as I know, there is a preview version of SmalltalkDoc in the new VisualWorks 7.3 release. But if it didn't make it into the release, you can still load it from the Cincom Public repository. It would be great to get some feedback on what we've done, but please remember that this is a preview release, subject to the winds of change.