Annoyingly, I have yet to find a good book that has an index by ingredient, as obvious as something like that sounds. In that regard some random googling comes to the rescue. I have a little notebook in which I compile drinks and ideas I can't find in books.
The Joy of Mixology, by Gary Regan, has an excellent taxonomy of drinks by major classification (i.e. grouping similar styles of drinks together), then by base spirit, and then by other ingredients. This is the first place I go to when I want to look for new drink ideas using a particular ingredient.
The accompanying iPhone app, Flip n Drink, has a search function to search by ingredient. It's a little clumsy, but handy.