Basic question about web queries

I'm trying to figure out how to create a web query that can have
substitutable parameters in it, where the parameters come from cells that are
referenced by the query.

For example:
suppose the following web query:
http://www.quoteserver.com?symbol=MS...5&format=close
returns the closing price for Microsoft on December 5th.

In my spreadsheet, Column A has a list of tickers, column B has a list of
dates, and I want the query to fill in column C with the closing price for
each ticker and date combination.

I don't want to have to write each web query separately since the list of
tickers I track changes; I want to have one query that can reference the
tickers and dates in columns A and B, and then look up the closing price.

Is this possible? Can anyone tell me how to do this or point me to an
example spreadsheet I can study?

Thanks in advance.
- David