Excluding empty parameters

I would like to exclude any parameter that is empty from the SELECTcommand? How do I do this? This is part of a storedprocedure.
SELECT PersonID FROM Persons WHERE
(FirstName = @.firstname) AND
(LastName = @.lastname) AND
(SSN = @.ssn) AND
(AddressID = @.addressid) AND
(DOB = @.dob) AND
(Middle = @.middle)
THanks
One way to do that is to pass a NULL value for the parameters to be excluded, and then structure your query like this:

SELECT PersonID FROM Persons WHERE

(FirstName = ISNULL(@.firstname,FirstName)) AND

(LastName = ISNULL(@.lastname,LastName)) AND

(SSN = ISNULL(@.ssn,ssn)) AND

(AddressID = ISNULL(@.addressid,AddressID)) AND

(DOB = ISNULL(@.dob,DOB)) AND

(Middle = ISNULL(@.middle,Middle))

|||Thank you Teri - As always you answer me SQL questions!