You have two options available to you. The first, as Partick mentions, is sp_helptext which will dump the text of the stored procedure from the syscomments table. The second is to use the object browser in the Query Analyzer that ships with SQL Server 2000. Just press F8 to open it. You can then navigate to the database of interest, then stored procedures. Right-click on the stored procedure of interest and select Edit.

-Mike