Hello, Ratan, and welcome to chatbots.org.
There are several options available to you, depending upon what sort of experience and skill you have in certain areas. I’ll list a few of these options here, to give you a fair starting point from which to investigate further:
1.) Pandorabots - This is one of the easiest to set up and run from your own website, and there’s a really comprehensive tutorial about getting started.
2.) Personality Forge - This is the home of some of the best chatbots out there, such as Bilgesmythe and Brother Jerome. I don’t have a chatbot here, so I’m not as familiar with PF as I would like to be, but given the quality of their most prominent chatbots, I’m sure that hosting a chatbot there is a worthwhile venture.
3.) Program O - Unlike the other two options I listed, Program O is NOT a bot hosting service. It is a chatbot engine, written in PHP and using mySQL, that will allow you to create and host your own unique bot using AIML. Program O version 2.0 has been recently released into Beta testing, and is nearing full public release. A good working knowledge of PHP and mySQL isn’t strictly necessary to use the script, but it certainly doesn’t hurt. Given that this option installs in your own web space, it’s a bit more technically involved than the other two, but there’s also a greater degree of flexibility here, and with experienced webmasters can be the better option.
4.) RiveScript - RiveScript is the brain child of Noah Petherbridge, and is a relatively new chatbot scripting language. There’s a great tutorial on the site, and a choice of three different “engines”, or interpreters that you can use for a web interface: Java, Perl and Python. This is a script that is well worth checking out.
5.) ChatScript - Written by Bruce Wilcox, ChatScript is a combination stand-alone chat engine/interface and chatbot server that comes with it’s own scripting language that is flexible, unique, and fairly easy to learn. ChatScript has powered several award winning chatbots, including Rosette, winner of last year’s Loebner Prize Competition, and Angela, who took second place in the same competition this year.
There are other options available, but this should get you well started. Many of the creators or developers of these scripts and services frequent these forums, and this is where the official support forum for ChatScript is located (in it’s own section, of course). Any one of these options could be a good fit for what you need, so I humbly recommend that you check them all out, and see which one best suites your needs.