Appointime - the online appointment scheduler

Long term, I'd love to build a site for my sister, a massage therapist, that allows her to build a base weekly schedule that auto-populates two months out, but gives her the ability to change individual days.  Customers will be able to log in and schedule an appointment and receive a confirmation e-mail.  A few hours before their appointment, they will also receive a text message reminding them of their appointment; I would love for them to be able to text back and cancel if they need to cancel their appointment.  Her site should integrate with Yelp for a review average and Flickr so customers can see her massage studio from pictures she has taken on her Flickr account.

Long term, I'd also love to build in the ability to pre-pay for individual massages and massage packages, and have my sister be able to charge $20 for a missed appointment.