The website http://www.eatyourbooks.com was mentioned by a food journalist in todays paper. I had a look at it and it could be a powerful tool if you have heaps of cookbooks as I do. Note it costs money but you can sign up for a free trial period of 30 days which I have done to see if it works for me.
Basically it has indexed large quantities of cookbooks, you "build" your own bookshelf with titles you own and then are able to search your collection for recipes by name, author, ingredient etc. From a brief foray I will continue to build my bookshelf and using it for the trial period and most probably will sign up.
Whilst I often search on line for recipes due to the ease of the searching, I do love my books and love the idea of having a search tool for them.
Worth a look.