In preparing my 2008 Federal tax returns, I have not been able to locate the confirmation of a stock purchase of Anhauser Busch made in 1996. The company, has since been sold. How can I obtain the information relative to my purchase of this stock i.e. date of purchase, price paid,commission etc.

Get in touch with your local Stock Exchange.
Try and get the CODE for the stock you hold.
Quote them the name of the Company.
There might have been a change of name.
Once you find this information , see what is the latest quotation on the stock.
When you get this information , get in touch with an investment service and decide what you want to do with your old investment.

If you can't find a copy of your trade confirmation in your files, try contacting your broker to see oif he can send you the information. If that doesn't work, you can estimate the purchase price per share using the average of the high and low price on the date you acquired the stock. Below is a link from Yahoo! To a listing of stock prices for BUD from 1996.
BUD: Historical Prices for ANHEUSER BUSCH COS INC - Yahoo! Finance

Remember that the stock split 2:1 on Sep 13, 1996 and Sep 19, 2000. So if you bought before Sep 13 1996 you divide your original purchase price per share by 4. If you bought between Sep 13 and Dec 13 1996, you divide the purchase price per shar by 2.