I move databases aaround quite a bit, so I created a little script to do this for all of the logins in the database.
Mike
DECLARE @sLogin VARCHAR(50)
DECLARE cursor_LoginList CURSOR FOR
SELECT NAME
FROM sysusers
WHERE status = 2
AND NAME <> 'dbo'
AND NAME IN (Select name from master.dbo.syslogins)
OPEN cursor_LoginList
FETCH NEXT FROM cursor_LoginList INTO @sLogin
WHILE @@FETCH_STATUS = 0
BEGIN
PRINT ' '
PRINT 'Fixing Logins in Current Database for ' + @sLogin
EXEC ('sp_change_users_login Update_One ,' + @sLogin + ',' + @sLogin + '')
FETCH NEXT FROM cursor_LoginList INTO @sLogin
END
Deallocate cursor_LoginList