Yaws and Mnesia
I wrote a Yaws appmod the other day that is quite useful if you are using Mnesia and Yaws. It can be downloaded here.
Just put in your path, configure it as an appmod in your yaws.conf and point your browser to your server with ymnesia in the path.
You will be presented with a table containing all your Mnesia tables and their fields, where you can search on arbitrary Erlang terms (nb: atoms need to be single-quoted).