Thanks Syrinx,
The only problem is that this is a very busy site and has many visitors, so it is very hard to manually go through the logs and trace users movement and match it to IP addresses.
Sometimes we don't get to check the logs until hours after the visitor has signed up and also they come from different timezones and separating all these facts to find a user IP address is not easy.
I see that the geo plugin for the CB can even log the new members' geographic location on the sign-up and display it on a google map, so I don't suppose that it will be hard to capture a user IP address when they fill up the membership application. Facilforms includes a lot of personal information including the IP, browser and OS information with the submission of every inquiry, so I suppose that Joomla is already facilitating the tools for this operation.
Regards,
JD