Already Presented
Check out Dragon #306 - "Power Fantasy" by JD Wiker.
The basics are as follows.
THROWING AN OPPONENT
(This is an addition to the grappling rules of the DMG, for use when a convenient drop is nearby or when the thrower is exceptionally strong.
* Add “Throwing an Opponent” to the list of options for Grappling after pinned.
* As the foe remains pinned only for one round, the pinning character must make a subsequent attack to use the Throw Action.
* When using the Throw Action, you can always drop the foe prone in your square (or any square you occupy), but if distance is the desire, assume that you can throw an opponent weighing no more than 1/3 of your Light Load rating out of your square. If you are actually trying to target a specific spot, treat the foe as an improvised ranged weapon (-4 non-proficiency penalty on the attack roll with 10’ range increment). If you are large enough to throw the foe one handed this counts as a standard action, otherwise it is a Full Round action.
* You can throw foes that weigh more than 1/3 of your Light Load, but not as effectively. To determine distance traveled, make a Strength check. The base distance is 5’ plus 1’ per every 2 points by which your Strength check results exceeds 10. Then compare the opponent’s weight with your load ratings and consult below.
Opponent’s Weight............................................Total Distance Thrown
Less than Light Load but more than 1/3................Triple Base Distance
Less than Medium, more than Light......................Double Base Distance
Less than Maximum, more than Medium.................Base Distance
Less than Maximum weight you can
..........Lift off ground, more than Maximum............No more than 5’
* When you want to throw a foe at a specific target (such as another foe), make an ordinary attack roll and then roll a Strength check to determine if you can throw the foe that far. Treat the thrown foe as an improvised weapon. If the throw would reach, but misses, the creature thrown lands in the target’s square. If aiming for a square, use the grenade-like weapons table, but do not roll for deviation unless you miss and threw the opponent more than 5’. Using these rules means that your foe could actually land farther away than you intended, depending on the deviation roll. If anyone is in the square where the foe lands, they must make a Reflex save (DC 15) to avoid being struck.
* Damage dealt by a foe used as a thrown weapon equals 1d6 points per 200 lb. of the opponent’s weight plus your Strength modifier. Apply this damage to both the thrown foe and any target it strikes. If the results of the throwing attempt allows a toss into a square where the ground is lower (such as a pit), add the appropriate falling damage.
Hope that helps.