Haven't you heard? Google is changing their traditional policy on """side loading""" apps and are, quite soon from now, planning to lock the whole thing down and make users submit to anal probing to opt out. Android has been good but times are changing and we need to stop trusting old institutions.

That's cool, but on a practical level, can I generate whatever the APK equivalent for iOS is and just give it to my friends with iPhones?

Yes. They will have to reload the app every 7 days, but yes.