Grant execute permission for a user on all stored procedures in database?

Without over-complicating the problem, to grant the EXECUTE on chosen database:

USE [DB]
GRANT EXEC TO [User_Name];

Create a role add this role to users, and then you can grant execute to all the routines in one shot to this role.

CREATE ROLE <abc>
GRANT EXECUTE TO <abc>

EDIT
This works in SQL Server 2005, I'm not sure about backward compatibility of this feature, I'm sure anything later than 2005 should be fine.