I'm using mod_auth_mysql to authenticate my users via Basic Authentication and a MySQL database. User and group is then available via my environment variables to my perl scripts (note this is a non-mod_perl solution).

It's a bit of a pain to install, mainly because the maintainer and primary website has vanished, but the code still works (available from the Mysql site contribs), and it's open source so you can correct it as needed. The trick to installing it is realizing that it wants the _build_ directories for apache and mysql, not the _install_ directories. (Why, I don't know).