Newbie stored procedure question

I'm trying to create a stored procedure that will generate and return a unique identifier when called.

Here's my stored procedure code:

CREATE PROCEDURE sp_tc_createuniqueid AS

DECLARE @uid uniqueidentifier
SET @uid = newid()

RETURN @uid

I'm getting the error: "Operand type clash: uniqueidentifier is incompatible with int"

After a few Google searches, I'm stuck as to how to fix this. Help!

Thanks.