Great ideas all! Thank you very much. I think I will go with at least a business card in my wallet, but I will forward the email to myself so it's on my phone just in case.
Coincidentally, I'm currently on a project to consolidate and update all of my emergency information. I am keeping sheets taped to the wall on each floor of my house with family and emergency phone numbers, but I always thought "if I update them, what if i miss one?" I agree with the poster who said it's a good idea to have multiple copies, plus a "master list" of where all the copies exist so you can check them off for replacement as you update.