You can find excellent Pilates classes online. Below is a list, with descriptions, of those websites I think have the best Pilates classes by online video. These sites offer Pilates workouts and specific exercise instructions, as well as exercise techniques and instruction on the use of Pilates equipment, including reformer exercises.
I recommend these sites based on their level of instruction, the quality of videos, and the range of classes offered. Because they are in-depth, these sites are not free. However, fees are reasonable and there are introductory offers.
Pilates Anytime is an exciting website offering online Pilates classes - mat, equipment, props - for all levels, and different interests. This site is special because it features a wide variety of excellent instructors and they add new videos frequently. In addition to their regular instructors, what they call the "distinguished instructor" list at Pilates Anytime includes many Pilates masters such as Kathy Corey, Michael King, and Jullian Littleford among many others. This website is easy to navigate and personalize. It is the place to go online if you are an instructor or looking for more in-depth instruction.
$18/mo. 15 day free trial
The video classes at Ultimate Pilates Workouts are taught by the owners of Pilates on Fifth in NYC, Katherine and Kimberly Corp. Katherine and Kimberly are delightful instructors with a Stott Pilates background. Ultimate Pilates Workouts has a offers a selection of classes, but it is easy to sort and choose workouts by equipment, level, and time. There are also lessons for Pilates instructors, offering cues and tips on teaching Pilates exercises.
Package deals from Free to 259.99 yr.
The Corp sisters are also featured Pilates instructors here at pilates.about.com. See: Pilates Exercise Videos at About.com
Read my review of Pilates at Gaiam TV
$9.95 per month
Pilates Interactive is a project of BASI Pilates, a company founded by renowned Pilates master Rael Isacowitz. A wonderful resource for advanced students and professionals, Pilates Interactive offers exercise instructions and full workouts for all levels and types of equipment. The site includes written instruction and video. Most videos feature Rael Isacowitz, which is a delight in itself. The site is searchable by a number of criteria such as by level, muscle group, or apparatus.
Site function take a little getting used to, but it is worth the effort.
$9.99 mo. $99.00 yr.
Pilates DVD Review: System 17 by Rael Isacowitz
Book Review: Pilates, by Rael Isacowtz