Great, thanks everyone! I have frozen them in the past, but freezer space is at a premium - we live in a rental and have a pretty small (for our needs) fridge/freezer unit. I considered just making my regular roasted green chile and tomatillo salsa and canning that, but I love the idea of preserving them whole so they'll be more versatile. Thanks again for all of your helpful input!

That's a good resource link, Tiggy. In general, you can process tomatillos using the same methods for tomatoes.

For whole Tomatillos, boil them for about 5 to 10 minutes until tender. Then pack into jars. Add boiling water and about a Tablespoon of lime juice per pint. Regardless of how you process them, you do need to acidify them.

But you can process them either in a pressure canner or a water canner. Either one is fine and follows all the rules. Times for processing vary for the two. They must process in a water canner for a lot longer. About 40 minutes per pint in a water canner. Check your pressure canner for their recommendations.

If you're going to use the tomatillos as an ingredient for other recipes, freezing them works fabulously. Instead of hot pack canning them, have you thought about making a salsa or pickling them? I can imagine a pickled tomatillo in a Bloody Mary right now!

Would you consider freezing the tomatillos? I've had pretty good luck with that - just wash, dry thoroughly, and set on a baking sheet in the freezer until solid, then toss them into a heavy duty plastic bag and use as needed.

Here's a link to canning tomatillos from Oregon State:
http://search.oregonstate.edu/web/?query=canning+tomatillos&site=extension.oregonstate.edu&cmd=Search