The free app, which also runs on the iPod Touch, allows contact information and photos to be exchanged with another user nearby.
Handshake works by using Core Location coupled with other technologies to send address book cards over the air.
Straightforward to use, Handshake sends data over WiFi, 3G, and EDGE connections.
The iPhones don’t connect directly to each other – instead the connection goes via Handshake’s server, so it only works on the iPod Touch when there’s good Wi-Fi.
When first launched, it will look for the address book card – or the user to specify a card if that can’t be located.
Handshake then connects to its servers and the user’s card, contact’s card or a picture can be sent by selecting one of the main three buttons.
The app also allows the default card to be changed by choosing the wrench in the top-right corner of the application and hitting the blue arrow under "My Card".
Available from the iTunes Store it comes in two versions: free or the ad-free paid option. An updated version is due out any day.