In no particular order as I remember them...
1) Unless a power or item specifically states that it does something after a charge attack, a charge ends your turn. This means you can't use a free action after a charge, but, if you have something that is an immediate reaction and it is triggered by the charge, you can use it because immediate reactions don't have to be part of your turn.
This is incorrect, for two reasons.
First, a Free action can indeed be performed after a charge. This is clarified by the FAQ for Player's Handbook 2 at
FAQ for Player's Handbook II! which clearly states this in the answer to question 6.
Secondly, Immediate actions can never be used on your turn, as per page 268 of Player's Handbook.
2) Charging is a standard action, and as part of it, you have to move at least 2 squares. You can move, run, teleport, etc. as a move action prior to moving these two squares when charging. You can move up to your standard movement rate as part of the charge action.
While you must move at least 2 squares, this movement must be "directly to the nearest square from which you can attack the enemy." (PHB 287) This means creatures with Reach must stop at the full extent of their reach, including PCs wielding reach weapons. "directly" is also important, you cannot wander around obstacles as part of the charge, though certainly as it is movement jumps are allowable.
4) The movement that is part of the charge has to put you in the space closest to your enemy from your starting position. You can use your move action to run circles around your enemy, but your charge action must essentially end in the space you can attack the enemy that was nearest your starting position. If that space is occupied you CAN'T CHARGE.
All true, but remember that given that diagonal movement is the same as non-diagonal movement in 4e, the problem if "the" square being filled comes up rarely (only on hard diagonals) and can be fixed easily, with a lateral shift with your move action prior to charging.
6) Every rule to charging has an exception granted by a power, feat, item, etc. Watch out for those.
The major hit list for these include :
- Badge of the Beserker (Neck) : Movement made as part of a charge does not provoke OAs.
- Vanguard Weapon : Extra 1d8 damage on charge attacks
- Boots of Adept Charging : Shift 1 after a charge
- Horned Helm : Extra 1d6 damage on charge attacks
- Marauder's Armor : +1 AC after charging until next turn.
- Fast Runner (feat) : +2 Speed when Charging (and running)
- Roundabout Charge (paragon feat): Charge to any square adjacent to the target.
7) Unless a power, feat, item, etc. lets you do something else, the attack at the end of a charge is a Basic Attack or a Bull Rush.
Not just a Basic Attack, but explicitly a Melee Basic Attack. Anything that can be used as a Melee Basic Attack can be done at the end of a charge, plus many powers have a Special note stating they can be used in place of a Melee Basic Attack at the end of a charge. This can include encounters and even some Daily powers.
Charge can be very very powerful, I have an Orc Barbarian who is a charge specialist, it can be a very potent attack when you learn to work with it.