finding a proxy address in exchange 2003 - aliase addresses

I may have posted this before, it is still worth pasting here
http://www.danlance.co.uk/index.cfm/2007/11/14/How-to-find-the-user--entity-an-email-address-is-associated-with-in-Exchange-2003

again I copy / paste from above source

Open the Acive Directory Users and Computers Management Console

Right Click on the domain > Select Find

Select Custom Search in the Find field

Select the Advanced tab

To find the entity with the email address spamtrap@danlance.co.uk for example, enter the following in the LDAP query field:

(proxyAddresses=smtp:spamtrap@danlance.co.uk)

This will list the entity containing the email address entered.

Wild cards can be entered within the email address (*) to return multiple matches.

If you want to view all the email addresses within the results list, select View > Choose Columns... and select Proxy Address - doing this in assoication with the query (proxyAddresses=smtp:*@danlance.co.uk) will give you a list of all entities within the organisation that have an email address, together with all the email addresses they have.