The R&A and USGA both allow for the use of distance measuring devices at the discretion of the tournament committee.
From Rule 14-3 of the R&A Rules:
http://randapublic.loghar.com/flash/rules/..._2008_2011.htmlQUOTE
Note: The Committee may make a Local Rule allowing players to use devices that measure or gauge distance only.
From Rule 14-3 of the USGA Rules:
http://www.usga.org/bookrule.aspx?id=14280...680221811460259QUOTE
Note: The Committee may make a Local Rule allowing players to use devices that measure or gauge distance only.
As has already been mentioned, distance information is not considered advice.
From Decision 8-1/2 of the R&A Decisions:
http://randapublic.loghar.com/flash/decisions/decisions.htmlQUOTE
8-1/2 Exchanging Distance Information
Information regarding the distance between two objects is public information and not advice. It is therefore permissible for players to exchange information relating to the distance between two objects. For example, a player may ask anyone, including his opponent, fellow-competitor or either of their caddies, the distance between his ball and the hole.
Except when the Local Rule allowing the use of distance-measuring devices has been adopted (see Note to Rule 14-3), information regarding distance must not have been obtained from an artificial device used during the stipulated round. A player who obtains distance information that he knew was measured by anyone with an artificial device during the player’s round is disqualified under Rule 14-3. (Revised)
From Decision 8-1/2 of the USGA Decisions:
http://www.usga.org/bookdecision.aspx?id=1...166358595194084QUOTE
8-1/2 Exchanging Distance Information
Information regarding the distance between two objects is public information and not advice. It is therefore permissible for players to exchange information relating to the distance between two objects. For example, a player may ask anyone, including his opponent, fellow-competitor or either of their caddies, the distance between his ball and the hole.
Except when the Local Rule allowing the use of distance-measuring devices has been adopted (see Note to Rule 14-3), information regarding distance must not have been obtained from an artificial device used during the stipulated round. A player who obtains distance information that he knew was measured by anyone with an artificial device during the player's round is disqualified under Rule 14-3. (Revised)