Hero's Bow

The Bow is Link's, Young Link's and Toon Link's Neutral Special in all the Smash Bros games that they appear in, Except for Links neutral special in SSB it is the Boomerang instead. There are differences with each Link's Hero Bow, though they all involve firing an arrow which is useful for stopping foes or camping, and holding B will greatly increase the range of the arrow fired.

Hero's Bow
Hero's Bow (Bow in Melee) is Link's and Toon Link's Standard Special Move attack in Super Smash Bros. Brawl. As pointed out by Sakurai, it is faster than its Melee counterpart. Even when the attack isn't charged up, the arrows fly farther than in Melee. Toon Link's arrows shoot at a very slight upwards angle and have a noticeable shorter range than Link's.

Link can still hold the arrow in place when it's fully charged. A fully charged arrow is strong enough to KO a person in Sudden Death. A fully charged arrow also has great range, useful for stopping approaches.

Link can turn around in mid air, if the backwards direction is pressed right after the bow is taken out. However, if combined with the Quickdraw technique, a glitch may occur in which Link points his bow in one direction, but the arrow is fired in the other direction. This can be avoided if the bow is initiated in the air just before Link touches the ground, instead of the same instant Link touches the ground. This move is notable for being used in the Quickdraw technique.

Fire Bow
Fire Bow is a variation of the Hero's Bow, and it is Young Link's Standard Special Move in Melee. With this version, Young Link shoots flaming arrows that do not travel as far as Link's and do slightly less damage. However, it has more hitstun than the other bows, and sets the foe on fire.

Origins
The Bow is one of Link's main weapons in The Legend of Zelda series. In Ocarina of Time, Link could use fire arrows, as well as ice and light arrows. In Melee, Link and Young Link's bow are based on its Ocarina of Time appearance; this is odd, as Young Link could not use the Bow in Ocarina of Time, but had his own version in Majora's Mask. In Brawl, Link's bow is derived from Twilight Princess, while Toon Link's is from The Wind Waker.