From the USGA book on holding a competition:
2. Teeing Grounds
As stated in Section 3-1, it should be decided in advance which area of each tee is to be used during the competition. In competitions extending over several days, the USGA normally recommends that each such area be no more than ten yards in length. The tee-markers should be installed within this area each day and balanced so that the course will play about the same length in each round. The practice of setting up a course to play progressively longer during each round of a competition is not recommended.
It is recommended that a sign containing the hole number, yardage and par be established to the side of each tee, at the center of the area to be used. Tee signs are particularly important if some players will be unfamiliar with the course. Such signs might prevent a match or group from inadvertently playing from a wrong teeing ground.
If signs are not feasible, it is suggested that the hole number be painted on the ground on each tee with a paint gun.
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Granted, it's not needed for everyday play, but it does give an interesting perspective.
This is what we used at our club:
http://www.paraide.com/product_detail.aspx?pid=452&cid=29