I would echo those who suggest considering if nap is necessary. We had problems getting DD to bed early when she was 2.5 years old, and she had naptime in daycare/school. When she moved to a school where naps were optional (around 2.75 years old), we ended up having the nap dropped and bedtime was so much easier (except on those rare days when she does nap for longer than 15 minutes, for instance on long car rides - then we were staring at late bedtime for that night). They just skipped the naptime instead of trying gradual decrease of naptime (partially because DD was notorious for being super cranky when woken from naptime) and it took a week or so to adjust.
aquinas, we had the same issue with DS - nightly readathons. even now, if left alone with his books, he would read until he falls over (sometimes literally - we had come back in to tuck him in, and found him asleep facedown on an open book in his bed) so we still have to watch that he goes to bed on time with books put away and lights off (luckily he is not inclined to turn on the lights behind our backs or find a flashlight so far).
