You may know what is Tor; it is a free application that lets users to surf the web, access email and instant messengers without being monitored or blocked by your internet service provider.
The developers of Tor has now released a free Android version of Tor known as Orbot which will brings the features and functionality of Tor to the Android mobile operating system.
Orbot works differently on different versions of Android phones. Android 1.x devices (G1, Hero, Droid Eris, etc) require the ProxySurf” browser installed to use, which can be downloaded from the Android Market.
For Android 2.x devices (Droid, Nexus One, etc), you must root your device for Orbot to transparently proxy all TCP traffic. For non-rooted phones, you’ll want to manually configure it for your specific needs.
You can get more information and download from here.