You can book railway tickets online using irctc.co.in. To do this you may need railway station codes, even if you can search station names on the site, it may take time to load the list. You can get it from that website itself, but that is a little slow. So you can find a list of railway stations and railway station codes from the following website. These links are to Indian Railway Fan club website.
First section below will connect the Railway station codes to station names. It is divided in to 3 section based on the starting letters of the station code.
The section below will help you to find the railway station code from the railway station names. You can open the corresponding link and find the code you want. (These links are divided based on the starting letter of the railway station names)
Some other useful sites, these are official websites of Indian railway.
The new website for train ticket booking seems to be a better one with speed and user experience. The SBT and and some other nationalized banks are not available on the payment section. It is expected that they will be added with in a short time after testing them.