I recently came across the 'bump' application developed by Bump Technologies. This application is available for both the iPhone and Android based devices. Using bump you can share your contact information between devices, simply by bumping your devices/hands on each other and let the inbuilt accelerometers' do the rest.The bump application also allows Facebook connectivity which makes adding friends extremely innovative and easy.
The video which follows demonstrates 'Bump' working between an Apple iPhone and a Google Nexus One. published by Android Central.
source - Bump Technologies