Which of these is the correct usage "working [with / on / in]"?

Solution 1:

I am a developer working on Microsoft technologies.

This sounds like you are working for Microsoft on their new technologies. If that's true, then you should state what the technologies are.

I am a developer working in Microsoft technologies.

This sounds like you are working for a division of Microsoft called "technologies".

I am a developer working with Microsoft technologies.

This sounds like what you are really after: you develop using Microsoft technologies.

Perhaps a better way to say this would be:

I develop web applications using Microsoft C# and WCF.

... or whatever the real application area and technologies are.