Every so often a publisher asks me if I can recommend any magazine app conversion services. I've actually been asked this enough times that I put together this list of companies. It's not a complete list, and the companies don't all provide the exact same services. I haven't used any of these companies, so I'm not completely familiar with what each one does and how they operate.
This list, like most of my resources, is a work in progress. Please let me know if there is a name that I should add. BTW, this list is just for periodical app makers, not ebook app makers. That would be a much larger list.