According to the FIFA laws document

Handling the ball
Handling the ball involves a deliberate act of a player making contact
with the ball with his hand or arm. The referee must take the following
into consideration:
? the movement of the hand towards the ball (not the ball towards
the hand)
? the distance between the opponent and the ball (unexpected
ball)
? the position of the hand does not necessarily mean that there is
an infringement
? touching the ball with an object held in the hand (clothing,
shinguard etc.) counts as an infringement
? hitting the ball with a thrown object (boot, shinguard etc.) counts
as an infringement
Disciplinary sanctions
There are circumstances when a caution for unsporting behaviour
is required when a player deliberately handles the ball, e.g. when a
player:
? deliberately and blatantly handles the ball to prevent an opponent
gaining possession
? attempts to score a goal by deliberately handling the ball
A player is sent off, however, if he prevents a goal or an obvious goalscoring
opportunity by deliberately handling the ball. This punishment
arises not from the act of the player deliberately handling the ball but
from the unacceptable and unfair intervention that prevented a goal
being scored.

This is from the Laws of the Game document (warning 2MB pdf)

User Posted Link

Page 55 onward contains info on interpretaion of the Laws.

Posted By: watfordcanary, May 7, 12:33:55