IRCTC (Indian Railway catering and tourism corporation) recently announced ticket booking via mobile phone feature. There is a android app to book your train ticket in any android smart phone. The application contains mobile app version of the IRCTC mobile website. The application takes you to the bookmarked mobile site https://www.irctc.co.in/mobile the payment mode is CITIBANK as a payment gateway after selecting it you can use other bank's debit and credit cards also. This is totally free android application.
Here is a step by step video tutorial for how to use this application
To download this application go to android market through this link IRCTC Book Tickets via Phone