The Alhambra is the most-visited monument in Spain... so, if you want to visit it (and you'll probably want) get your ticket as soon as possible.
All the information about visiting this Red One (that's the meaning of Alhambra) is available at http://www.alhambra-patronato.es/index.php?id=8&L=2.
Do not forget to wear your hat/cap/whatever-you-use-to-cover-your-head and a bottle of water.
Prices are between 7-25 Euro / person depending on the type of visit.
You can buy your tickets at Ticket Master. Tickets for september can already be bought.
Finally, you can also buy the official guide of Alhambra for both iOS and Android.
Are you interested in visiting the Alhambra with other fellow YAPCers? Please say below which day you're interested/have booked so that other people can contact and join you.