Voxer Walkie-Talkie is a communications app that lets you use push-to-talk walkie-talkie features, send text messages and images, and share your location. But it's important to note that the default is to share your location, and not everyone will be comfortable sending that information.
What makes Voxer useful (for those who don't have unlimited voice plans) is that it doesn't use up minutes from your carrier; it only uses your data allowance. And even with a lot of voice messages, photos, and texts, it uses only a small amount of your data pool. Sprint, which was known for its push-to-talk walkie-talkie capabilities,for good at the end of June, leaving Sprint users without push-to-talk features, but with this app, you'll be able to use push-to-talk on your iPhone regardless of which carrier you're with.