Gantt charts in Trac
This plugin is hosted here. (bad link -- access denied!)
Dont forget to read the README file included in these files, it contains important changes you need to make for your configuration so that gantt works.
Fixes for 0.11
Here is a patch to make it run on 0.11: http://www.freebsd.org/cgi/query-pr.cgi?pr=ports/126112 1212123
Someone nice applied this patch to the 0.10 compatible source and distribues the patched source here.