DropdownLIst Box Question, Stored Procedure

Hi All,

I have a dropdownlist box with values  (All, Paris, London, New York) -- Cities

Another dropdwonlist box with values (All, Bank of America, City Bank, CIBC) -- Banks

And have a stored procedure that populates the info:

CREATE Procedure Search
(
    @City nvarchar(50),
    @Bank nvarchar(50)
)
AS SELECT     * FROM     TableA WHERE 
city = @city AND bank= @bank GO

If user selects a value anything other than "All" in both dropdownbox, everything is OK.

My question is, if user selects "All" in any of these dropdown combobox, how can I seach for all Cities or Banks.

SQL needs to run as a stored procedure. If it was on client end, it would be alot easier.

Any ideas?

Thanks for your help.