I've seen some around years ago. I've been using Beersmith for my brewing needs and it does a good job for me. It has a Notes area. Just used it for the first time last night. It can print out a ""brewsheet" with instructions and information on your brew which you can use to brew by, or save for your own future reference.
I highly recommend Beersmith for nearly all brewing needs. You can try it out for a while and see how you like it.
If you prefer to do it manually (some do), try a search for brewing log or similar in Google. The first page gave me
THIS page with a downloadable Word document.
Damn, you guys are faster than me...