It will be quite complicated if you don't know HTML, ASP, and databases.
You need to create new input boxes on the registration page to collect the information.
You then need to read it in, and depending on what sort of data you are getting check it for any malicious code.
Once this is done it needs to be saved in the database, for this you need to create new fields in the tblAuthor table in the database to hold the new data setting the data type of the fields for the type of data you want to hold.
Once all this is done you then need to alter any page you wish to show the new info on to read in the data from the database then display it in the HTML. One of the main pages you will need to edit is probaly the pop_up_profile.asp page which will need to be edited anyway to remove the parts that show the ICQ, AIM, address, etc.