Screens for iOS requires iOS 5.0 or later.
… More Features
Screens for Mac requires OS X 10.7 Lion or later.
Your iMac at home sends its IP address to the Screens Connect server.
On the road, your MacBook, iPad or iPhone retrieves the address of your home iMac from the Screens Connect server.
From your Macbook, iPad or iPhone, you can connect to your home iMac over the Internet.
DownloadCreate a Screens ID