Website brokers and such would be your best bet. Example feinternational.com or anyone else that is reputable would be the best bet for you to sell your app.
Honestly it's more marketing hype then security. While they do have some good applications they have had some bugs in their phones that really question the $700 price tag.
Most of the security apps will require that the other person has the same apps. I find that rarely will people use those apps.
Thanks WMF. I was looking for a service that would have this as an API or infrastructure behind it. I would rather not have to build out something entirely from scratch.
I would say this, take your savings and double it before jumping in. Your going to realize that you might be spending more money then allotted for your project. Also make friends with internet marketers and such to help you raise awareness for your brand/company. I've made friends with startups and helped them get traction and they have hooked me up with their development knowledge (not work, just answers to questions) and such.
What's your plan if this doesn't work out? Hate to say it but just wanted you to think about it.