Just a quick and dirty reminder than when you are trying to make Trac plugins work, you need to make sure you are using the correct python version of the egg. For example, I recently wanted to add the RegexLinkPlugin to one of my Trac instances. However, when I downloaded the provided egg and installed it, nothing happened. Upon further inspection, I realized that the egg was for Python 2.5 and I was running 2.6 on my server. I downloaded the source and recompiled and was rewarded with a (working) Python 2.6 egg.
By the way, the RegexLinkPlugin is a nice way to map wiki text to links in your Trac installation. For example, I am using it on an IT wiki where each server has its own page but the servers are all referred to by all lowercase hostnames. Using RegexLinkPlugin I can map each hostname to link to the page for the server with no extra wiki markup, ensuring my users always generate the links when using the hostnames.