AOD's G/S-mode Calculator/Reference Chart version 1.0

Accuracy

Did the attack hit or the effect occur?
Accuracy:

Pokemon 1

Attacker's Level
Base Power of Attack
Attacker's original Attack/Special Attack
Attack/Special Attack Modifier
Defenders's original Defense/Special Defense
Defense/Special Defense Modifier
Effectiveness of attack
STAB (Same Type Attack Bonus)

Pokemon 2

Attacker's Level
Base Power of Attack
Attacker's original Attack/Special Attack
Attack/Special Attack Modifier
Defenders's original Defense/Special Defense
Defense/Special Defense Modifier
Effectiveness of attack
STAB (Same Type Attack Bonus)

Stat Modifiers

Stat modifier attacks are ones that increase or decrease one of the Pokemon's attack, defense, speed, special attack, or special defense. The modifier values start at zero, and are increased or decreased by attacks.

Attacks that greatly increase a statistic (like Swords Dance) increase it's modifier by two
Attacks that increase a statistic (like Meditate) increase it's modifier by one
Attacks that decrease a statistic (like Growl) decrease it's modifier by one
Attacks that greatly decrease a statistic (like Screech) decrease it's modifier by two

For Attack, Defense, Spec. Attack, and Spec. Defense-changing attacks, you don't need to calculate the new statistic, just put the modifiers into the calculator on the left, because Critical Hits ignore stat modifiers. If you're wondering (or someone used a Speed-affecting attack), here's a chart of how the modifiers change the statistic:
Modifier: -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6
Multiply stat by: 0.25 0.28 0.33 0.40 0.50 0.66 1 1.5 2 2.5 3 3.5 4

More reference stuff will come later