At the Media App Summit today, Vook VP of business development Matthew Cavnar urged attendees to “use platforms that are already out there,” reducing the cost of building a new app.

We’ve collected links to a number of services that will help you build an app with a pre-existing tools:

1. Free Demibooks App Building Tool for Writers

2. How To Make An iPhone & Android App Using Yapp

3. How To Make An iPhone App Using AppMakr

4. DIY iPad Publishing Tools from Genwi