you can easily see on vendors/AH what recipes you have already and what are available for you to learn or will learn..
I remember there was an addon that when you where scanning AH or vendors for recipes there was different colors on them which was
color A:Already have recipe
color B:An alt have this recipe
color C: Recipe is available for learn
color D: Recipe available for learn on alt
only one I found close to it is http://www.curse.com/addons/wow/recipe-known-v0-110 but is not updated to 5.1 and on comments I see people posting for errors. Is there anything else?
thanks in advance