Try

SELECT 
		DATEADD(minute, 1, m1.endTime) AS SlotBeginTime,
		DATEADD(minute, @gap, m1.endTime) AS SlotEndTime,
                r1.Description, r1.RoomAvailable 
	FROM meetings m1 
	LEFT JOIN meetings m2 ON ISNULL(m2.beginTime, @DateTimeEnd) > m1.endTime 
		AND (m1.roomID = m2.roomID OR m2.roomID IS NULL)
	LEFT JOIN RoomInfo r1 ON r1.roomID = m1.roomID
...

>One more question
>
>I need to add a join to this table to get information about the room, such as the description and RoomAvailable times. It is linked on the roomid field. Would you mind showing me how to add this join the to query.
>
>Thanks
>Kirk