My favorite is the video tutorial on decorating with magnetic paint. (tatertotsandjello.com)
I tried to use magnetic paint under my chalkboard paint once and it didn't work. (theinspiredroom.net)
If you put a dry erase board on one side, you could paint magnetic paint under the chalk board paint on the other side so that people can still tack stuff up. (susieharrisblog.com)