Automate "Week Ending" Date

How do i automate, by stored procedure, generating the "week ending" date using a field data.

------------------

CREATE TABLE [dbo].[t_Work_Hours] (
[WorkHoursID_PK] [int] IDENTITY (1, 1) NOT NULL ,
[PeopleID_FK] [int] NOT NULL ,
[JobID_FK] [int] NULL ,
[StartTime] [datetime] NULL ,
[EndTime] [datetime] NULL ,
[Title] [nvarchar] (1) COLLATE SQL_Latin1_General_CP1_CI_AS NULL ,
[WeekEnding] [datetime] NULL ,
CONSTRAINT [PK_t_Work_Hours] PRIMARY KEY CLUSTERED
(
[WorkHoursID_PK]
) ON [PRIMARY] ,
CONSTRAINT [FK_t_Work_Hours_t_Work_People] FOREIGN KEY
(
[PeopleID_FK]
) REFERENCES [dbo].[t_Work_People] (
[PeopleID_PK]
)
) ON [PRIMARY]
GO
-----------------

What i have tried has'nt even been close to a solution.
UPDATE dbo.t_Work_Hours
SET WeekEnding = DATETIME ( ? , StartTime) . I have no idea where to go!

--------------------
WorkHoursID_PK, PeopleID_FK, JobID_FK, StartTime, EndTime, Title, WeekEnding
7, 40, 3, 11/1/2005 6:00:00 AM, 11/1/2005 4:30:00 PM, J, (NULL)
8, 43, 3, 10/31/2005 6:00:00 AM, 10/31/2005 4:30:00 PM, F, 11/6/2005 11:59:00 PM
9, 43, 3, 11/1/2005 6:00:00 AM, 11/1/2005 4:30:00 PM, F, 11/6/2005 11:59:00 PM
------------------If you insist on performing an UPDATE on the field, then some variation of the statement below should suffice:


...SET WeekEnding =dateadd(day, 8-datepart(dw, StartTime), StartTime)...


I would make WeekEnd a computed column like this:

alter table add Weekend as dateadd(day, 8-datepart(dw, StartTime), StartTime)|||Should be in here somewhere

http://weblogs.sqlteam.com/brettk/archive/2005/06/02/5528.aspx|||thanks a bunch