The American Society of Media Photographers (ASMP) has made a model and property release app available for iOS: ASMP Releases.
"A must have app for professional photographers working in all genres of the business. Photographer can customize a Model or Property release using the ASMP standard releases. The app allows you to create templates, take a photograph of the subject, specify the uses for the images, including any sensitive or digital manipulation issues, and images of minors, the models can then sign the release and a PDF is emailed to the photographer, agent, model and client as needed. In addition to the ASMP forms, the app includes the industry standard releases for stock photography produced by Getty Images, Inc., for photographers planning to license images through a stock photography distributor or portal. Also included is a special release for promotional use by the photographer. This FREE app is provided by ASMP, the trusted industry resource for photography business answers."