Passing Parameter To SP Using IN

Hi,

I have a stored proc as follows:

Create stored procedure sp_test
@Cno nvarchar (1000) AS
SELECT * FROM Contracts WHERE Cno IN (@Cno)

How do I actually pass the parameters to the stored proc?

sp_test "'cn01','cn02','cn03','cn04'" doesn't work.

In VB.NET this doesn't work either:
dim s as string = "'cn01','cn02','cn03','cn04'"
cmd.parameters.add(new sqlparameter("@Cno",nvarchar,1000))
cmd.parameters("@Cno").value = s


I don't want to parse the string inside the proc and then Exec the parsed string.

TIA
Jeremy Holt