I am no expert in IT but what I could understand is that you are develping web applications as many programmers develop applications for social websites like 'Orkut' and ' Face Book' etc. Regarding qualification of software develped by you as Information Technology Software or not I am quoting the relevant definition
" Inforamtion Technology Software" means any representation of instructions, data, sound or image, including source code and object code, reconred in a machine readable form, and capable of being manipulated or providing interactivity to a user, by means of a computer or an automatic data processing mahcine or any other device or equipment".
Now you judge it for yourself whether applications develped by you qualify as nformation Technology Software.
If you think it is taxable and you have not collected and paid the dues my advice would be that you should assesse your duty liability as soon as possbile and pay all your dues along with interest for late payment @ 13% before the department serves you any demand notice which would save you from penalty which may go upto twice the amount of service tax not paid.