I highly recommend the Amer Acad of Pediatrics Potty Training book (you can get the name on their website and order it from amazon.com, etc). It is a great guide on how to watch for readiness signs, step by step instructions, etc. We also read ptrng children's books to our kids and watched Big Bear in the House video about potty training to stir the natural interest.
We began the process by letting the kids use the potty before bathtime, when they woke up, etc to get some success. After that, we just encouraged them and used a sticker rewards chart (sticker for sitting, sticker for trying, 2 stickers for peeing, etc) with an exciting prize at the end for completing the chart and being potty trained. With all that said, both of mine had interest starting at 18 mos so we "trained" off and on, but when they were truly physically ready, they were trained for day, naps and night in a couple of days. (we also never used pull-ups, just naked and underwear for the training days). Both my son and daughter were trained before 2 and a half.
Good Luck!