I am only a month or two ahead of you on this unit testing path. To the resources already listed in this thread, I would add the following:
and then grab a root shell; invoke cpan and use `i /Test::/` to see what is in the repository that could prove useful. There are lots of tools and resources on the net other than the ones listed here. But this covers most of the perl specific ones. But you might also want to spend some time with Google looking for Test Driven Development, Agile Development, Extreme Programming.
Trust that is helpful.