Yes, that's work experience but schools looking for management experience would prefer a role with a clearer managerial element.

Does that mean my exp wont be accepted by top b-schools? Well i am an engineer so i dont know much about management. So does that mean an IT person cannot get into a good b-school even if my job includes issue solving, guiding people throughout the issue, etc?

Well, lots of people apply to the top schools and to be admitted you have to be a much better candidate that most of the other candidates. With two or three years in IT, you are the most common type of applicant (especially as a male IT engineer in an Indian firm). Your work experience is work experience, so it counts, but it's not especially rare or desirable. Most other applicants will have more, and better. I think it would be helpful for you to read a book on MBA admissions. I recommend Balbir Singh's "The MBA Admissions Handbook". The third edition just came out but an older, second hand, copy will be just as good.

We have our own business, travel and tourism. If i work with him, will that exp be considered. If not, please suggest what should i do.

Your current experience will be enough for most US universities' MBA programmes. If you wanted to get into a top school you'd have to be a stronger applicant, and that is a book-length answer.

Which is best university for marketing?

See http://find-mba.com/lists/top-business-school-by-speciality/top-business-schools-for-a-career-in-marketing

Does name of the company matter? What if i work for an NGO. Will that better my chances?

Other things being equal, it would.

But does the company name considered while selecting students for admission into MBA?

Yes, if the company is one that hires from the business school, or is a very interesting one that adds something to the experience in the cohort.

So working in a small and unknown company is not good right?

If it's doing something very interesting, then that could be good. But a small and unexceptional company won't help you.

I am on 3rd party system. I work for wipro at client site price waterhouse coopers and i get paid by ITCONS. So what do you think. Is it good enough?

I think it depends on the university, and on your GMAT score and academic record. Certainly your work experience suggests you will bring little new experience into the cohort of most top MBA schools.