I signed on with MindBodyOnline in October 2007.  It was the best thing I've done business-wise since opening my studio.  It not only does scheduling and keeps track of your database, it also provides you with sales/income tracking, client visit tracking, instructor proficiency reports, and other useful information.  It is easy to use, and the customer service is great, and they help you right away if you need tech support.  Very high recommendations!

Just want to say ditto to MindBody Onine...I have been using it at Parker Pilates since August 2006- it is a business lifesaver...We use primarily for retail point of sale and class signups- etc. I have access to the appointment section- but we only use that side on the business side and have clients make their appointments the "old fashioned" way on phone to ensure we are available and no missed appointments etc. I hope to grow large enough some day to use the appointment section too ! They have great LIVE Technical support too !