We know that contact details come in a variety of shapes and sizes and you don't have to send the same set of details to everyone.
Easy.Share is an application that allows you to easily pick, choose and share a phone number, Facebook page, LinkedIn profile, your iPhone's UDID number and even your precise location to any number of people, with any kind of mobile phone. People you send your contact details to don't have to be iPhone, Android, Blackberry or Nokia users. You can send your details to people who don't even have a phone (although, there aren't many left).
Please note, the app currently requires iOS 4.1.4 or later.