This mod is called Gulliver. Itís named for the book Gulliverís Travels, though much of the inspiration comes from The Borrowers, Alice in Wonderland, and other size-related stories.

What it does

From the outside, it looks just like plain vanilla Minecraft. There are no new blocks or items, just two Potions.
But with Gulliver installed, you now have the ability to change your own size or the sizes of mobs & NPCs!
The world works differently when you and mobs change size. See what happens!

A few starter tips for tiny players:

Watch Your Step
Shift-Crouch to Jump 1 Block High
Some Blocks are Climbable!
Carry Paper, a Slime Ball, String and a Lily Pad
Carry something pointy (like a Stick or Sword), you may need it to pry open Chests or Doors
Try the Fishing Rod
Beware of Cats & Spiders!

A few starter tips for huge players:

Watch Your Step Ė Falling Hurts!
Shift-Crouch to Jump Half Your Height
Try Punching Blocks/Mobs Barehanded
Step On Mobs (or else Sneak Over Them)
Right-Click Mobs When Barehanded to Pick Them Up

Download: Gulliver Mod 1.6.2
You can also see all awesome Minecraft 1.6.2 Mods here: Minecraft 1.6.2 Mods
You can also see all awesome Minecraft Mods here: Minecraft Mods