Anyone know a not too toxic way to get rid of them in garden beds? 

We have a raised bed garden. Because we had snow on 3 May, we planted quite late. Yesterday morning everything looked fine. It rained in the night but we needed it. This morning the cantaloupe plants are dead with pill bugs making a feast of the leaves and stems.

First, my understanding is that the pill bugs aren't really killing your plants, but eating your plants because they are dead or dying.  I would be more likely to think that snails, slugs or such did the major damage.  In any event, you can try to spread Sluggo, which would stop the slugs/snails.  Insecticidal soap would work against earwigs, pill bugs, aphids and other that want to chew on the leaves, and finally you could scatter dia  tom ace ous about to discourage all of the above and any unidentified eaters in the night.  The Sluggo lasts for a while, but the insecticidal soap needs to be renewed fairly often while the diatomaceous earth is useless once it gets wet, so needs to be reapplied after every watering.  

What David said.

I know my reply is a little late, but you may also have planted too early or had a late frost. I did a quick search, and it looks like your last frost dates are in May, like mine.  http://www.victoryseeds.com/frost/ia.html