In reply to Michael Cuenco.

Hi Michael,
I am not aware of the feasibility to place "text" on the markers. However, you can create a set of different markers with different letters and different colors, and then you can have your data drive the logic of which image to display for a particular marker. You can find an example of this implementation in my blog post SAS to the rescue: claiming your location on Google map...
Please let me know if this answers your question.
Best regards,
Leonid