Sergio,
Yes, your client needs to have a SQL Server license ... after all, they are the one's running the app and using SQL Server. Now, if you're using MSDE instead of SQL Server, then no license is required.
~~Bonnie
>Hello Michael,
>Is the client of the aplication (the customer who you've developed an application for) going to need a license of SQL Server in order to use the application?
>
>Sergio