Well, I installed the download package on my website, but when I tried to add an archive to it, it just barfed and I don't have time to debug it right now.
So for the time being, you can download http://bitdojo.org/tagcloud-procs.txt and save it as packages/categories/tcl/tagcloud-procs.tcl.
The only public function can be called as
set tag_frag [category::tagcloud::tagcloud -tree_id $tree]
and will return an HTML fragment which represents the tag cloud. As mentioned before, the links to the object browser are problematic because of permissions issues I haven't sorted yet.
But if you try it and send me feedback, I'll try and fix it <g>
