Eliz, are you going to be replanting them immediately or will there be a delay?

If they're not going to be replanted right away, you can do several different things. First would be to dig 'em up, wash the soil off of them, cut back the foliage, and let the rhizomes dry a little. Then store them in peat moss (actually I'm not sure about that as mine stay in the ground year round) or even shredded newspaper. If you have to dig your cannas every year for Winter storage, just treat them the same way.

Or you could dig them up and pot them up.

Or you could dig them up, put them into large baggies with potting soil and leave it open. Just make sure that the soil stays moist. Make sure that you mark on the baggies their names. If you're going to be transporting them a long distance, the baggy method takes up less space than pots. Not to mention the time involved in potting them up.

I use the baggie method with alot of different plants that I dig due to needing to thin, etc., to hold them before either transplanting in another location or giving to friends and/or relatives.

If you don't want to deal with potting soil, you can also soak them in a bucket of water overnight (or however long you need to), wrap with wet paper towels/newspaper, put into a plastic shopping bag and tie it closed.

Hope this gives you some ideas.

Jenna