Hi, sureshbabus!
You might want to consider posting a draft of such a letter here, without putting any contact information in it, so that we can advise you as to how you might make improvements to it, that would be great! If you do that, I'm sure that they'll be those of us who'll be willing to come along and give you advice concerning it.
We can also help you with what you might say in person to potential clients/customers.
If you would like to know how to market and advertise what you have to offer via the Internet, without it costing you anything, please let me know on this thread.
Via clicking on the following links, you'll find samples of ways that you might draft such a letter that you might then tailor to meet your needs.
Sample Business Letters and Forms (http://www.4hb.com/letters/)
Free Sample Sales Letter: Example of How to Write a Persuasive Business Marketing Letter (http://www.articlesbase.com/direct-mail-articles/free-sample-sales-letter-example-of-how-to-write-a-persuasive-business-marketing-letter-849.html)
Introducing a sample introduction letter template tool to assist leaders. (http://www.leadership-tools.com/sample-introduction-letter.html)
Letter Samples - Free Letter Templates - Personal and Business Letter (http://www.letter-samples.com/)
Sample Business Letters and Forms (http://www.4hb.com/letters/)
Idea Cafe Small Business Archive: "Company introduction letter" (http://www.businessownersideacafe.com/cyberschmooz/marketingmix/3612.html)
Business introduction letter... Here's a sample business introduction letter. (http://www.writinghelp-central.com/business-introduction-letter.html)
Mid-career Job Offer Letter Sample: Introduction and Sample Mid-career Job Offer (http://humanresources.about.com/od/formsforhiring/a/job_offer_mid_2.htm)
Introduction Letters (http://www.writeexpress.com/introduction.htm)
Sample business letters by Quazell (http://www.quazell.com/BusinessLetters/default.htm)
Thanks!