Contacting right person in big companies

First, I want to know your opinion if I should contact Microsoft in this case and then to whom I should write.

There's an online customer need where some companies have fulfilled with different kind of solutions. From the technology point, they can be divided into two categories: PHP based solutions and Java based solutions.

We have made an ASP.NET solution with a new approach to the problem which I believe shows the advantage of Microsoft technology in this category. Also, since no previous solution is available based on Microsoft technologies, it may encourage other parties to use ASP.NET in this category (remember days of Joomla and PHP nuke in CMS category, when DotNetNuke doesn't exist, albeit this case is different).

Is it a good idea to contact Microsoft and introduce the product? If yes, to whom we should write?

Take a look at Bizspark. As well as providing free software the program is set up to support startups using MS tech. I imagine they are best placed to promote your product within MS.

Emails sucks due to spammers. So, don't keep an option of emailing to the desired official. There are hundreds of product managers for Microsoft. Find the name of at least one in them and send a fax to him. I believe this is one option.

Otherwise you can write a postal mail to the product managers. Either in fax or postal mail do not forget to include "Response required." - followed by your email address.

Otherwise you just ring to the Microsoft's general contact number and ask them to forward your call to the desired person or at least desired department.

And make your mind clear Microsoft does not blindly believe you and give appointment you explain them about the complete project that you have done and do not expect travel tickets or other allowances from them if you do, your appointment will be rejected. Go, meet them, explain them, if they are interested your life may change.

All the best..!

In addition to what John said (enrolling to BizSpark) I would also suggest to offer your solution on Azure. Microsoft is really looking for success stories for Azure, so that might be a good way to get visibility.