As a belly dancer and an enthusiast of Pilates, I have always found that practising Pilates is extremely useful to develop the muscles involved in a lot of belly dance movements. After all, Pilates is used a lot by ballet dancers as part of their training, so it can surely be good for other styles of dance as well.
The core muscles (abdominals and pelvic floor muscles) are the main focus in many belly dance movements, so it is extremely important that these muscles are very strong if a belly dancer wants to perform those movements correctly, without injuring her back. A lot of Pilates movements involve strengthening the core muscles.
A popular type of Pilates exercise, which I always use as part of my belly dance training, are planks. Planks are amazing in that they strengthen the abdominals like no other exercise and also there are many different variations for planks, which allow you to progress gradually. Having strong core muscles is also extremely important to perform the famous belly dance backbends.
Also, a lot of Pilates exercises involve isolating individual muscles and becoming aware of their activity. Again, this is very helpful in bellydance training, as in belly dance isolating single body parts is very important. Bellydance movements that involve isolations are for example undulations, belly rolls, hip circles, chest lifts and more.
Another aspect of belly dance that practising Pilates can help with, is posture. I always stress during my that good posture is paramount in belly dance, in order not only for the movements to look good, but also to make the moves possible and to protect the back.
Last but not least, Pilates helps improving balance by strengthening the core muscles. The stronger your core muscles are, the easier it will be to hold your balance, which is fundamental in dance, including bellydance, for spins and travelling steps.
A good instructional DVD, which provides a fusion of movement between Pilates and belly dance, is ‘Belly dance for Beginners Fitness Fusion PILATES’ by Suhaila Salimpour. Also, there are various books and instructional DVDs available for those who wish to practice Pilates, but of course finding a good local instructor is the best option, at least if you are new to Pilates.