Hi Sasikumar,
Speaking in a neutral accent requires patience and practice -- on the part of the learner.
For example, with our regional dialect, the word "love" is pronounced "lou" or "lubh" in different parts of the country. This is an example of MTI - Mother Tongue Influence, and it's not something that is bad - it's just something we learn as kids and never correct until it is pointed out.
One's pronunciation is also part of learning how to speak in a neutral accent, and this can be easily corrected too. So can grammar issues.
For grammar - the best book I have found is the "Wren and Martin," and it can be found in both first-hand bookstores as well as second-hand ones.
Having a neutral accent is NOT just necessary for "international business" -- it helps one to be understood by another person.
A lot of independent trainers, vendors, English training institutes organize classes for people teaching them the above. Another option is to try the "Active TM English" program offered by TataSky.
One thing to remember is to actually learn -- not just go for classes, etc. One can learn by actually putting into practice what is being taught, on a daily basis and on every occasion. This gives one the confidence to continue, and over a period of time, one learns how to have a neutral accent.
Another way is to "record" one's voice and have someone who can help hear and correct. Reading out loud helps, watching English-based programming, the news helps in familiarizing one about the language.
I hope this gives you a fair idea of how one can speak in a neutral accent.
Richa Joshi