Shepsy, the answer depends in part on exactly what information you need to track. The emails already contain the sender's name, their email address, the date and time of their enquiry, and the subject. If you want to know which part of your site the enquiry originated from, you could add a suitable code to the message header or body to indicate that (you would do that at the time that the message is generated).
If you want to do some sort of analytics on the messages, one option would be to write some simple software (or hire someone to do it for you) to extract those details from the emails and insert them into an Excel spreadsheet. You could then use all the features of Excel to extract whatever useful information you need.
If that doesn't answer your question, perhaps you could be more specific about what you are trying to achieve.