So, Apple's recommending that people write down their passwords just in case they forget them and need to look them up. Umm...yeah...that might just be a real easy way for someone to get all your passwords, no? Nevertheless, Apple's providing a nice form you can fill out, so if you really want it, head on over to their site and download away.
While most people probably won't do this, there are other ways to secure this data while making it easy for you get at. One such way that I've written about before is with EssentialPIM, a free personal information manager (think: Palm, just without the device it goes on). Other software tools include Evernote (absolutely great program) and LockBox, an online file locker for your information. Check them out and see which fits best.