topr8 - 9:29 am on Mar 3, 2011 (gmt 0)
these are queries or series that are saved in the database, it is just a different way of querying the database - personally i use them almost exclusively for everything, but that's a whole other question.
if i understand you, you are looking to display a product in its original currency and then for reference show it in the user's currency as well?
otherwise your plan on how to do it seems reasonable to me, the MSRp and the currency in the product table and a table with currency conversion rates.
i'd then do the calculation in php or what ever your server language is.
is the site informational? or are you actually selling the products?