Lookup Using Row And Column Names

I have two workbooks used for periodically updating product pricing to wholesale customers, one of which has all the product computation info and the other all the customers and products they buy. There is one main sheet in the product information book that has all the products going down the first column with a code for each item. The headings of many of its columns represent variations in packaging. The combination of product and package variations result in the customer's unique price.

I am seeking to find the intersection of product and packaging using names rather than cell numbers. Right now I am able to use VLOOKUP with the product name and named range from lookup sheet but I seem forced to use the column number rather than column heading name. As there are a lot of columns it's easy to lose track or make mistakes. Column name would be much preferred. We are still using Excel 2000.

Example of current reference:
=VLOOKUP("productname",mainlist,24,0)

I would like to use something other than 24 for the lookup column, like 'packagename' instead. I have reviewed the INDEX and MATCH functions but haven't figured out how to accomplish what I am after. Incidentally, 'mainlist' is a named range in a separate workbook but referencing as shown above has worked without a hitch.