A recent post linked to a paddle-based drill to help someone learn bilateral breathing; USMS has also recently posted a short article explaining how using paddles without the wrist straps can encourage better swim mechanics. I’ve found that paddles can be very useful training tools, and I have three different pairs in my swim bag. But which one(s) are right for you?
Mark Gangloff posted an excellent review of over a dozen paddles of various types on SwimOutlet.com. He does an excellent job not just of relating his impressions but explaining how different paddle designs might be useful for different purposes. Over on the USMS website, FINIS also does a good job of explaining this in an article titled Paddle Shape and Design.
Finally, USMS also posted a video review of paddles.