I've been working on it myself. Squats you probably already know about. Lunges are also very good (although I can't do them because they tend to bother my knees), certain leg presses will pull in your glutes.
For better isolation, you can also do kick backs on a hip machine, and a donkey kick glute machine. This of course only goes so far. I've maxed the weight on the lone glute machine at my gym and can do 20 reps in good form, so I'm looking for new ideas myself. :)