yes as of now
There isn't one natively included in Minecraft other than your hands. There are some available for download, such as VoxelSniper or Mcedit.
Minecraft forge is a free program.
MC Forge will always use its latest version. Therefore, backup your Minecraft and install your second Forge. Forge will use its latest version.
First, you google "minecraft forge minecraft forum". And click the first suggestion. Then the first minecraft forum member has posted a minecraft forge link to go to the website.
Minecraft Forge lists you all mods in minecraft and Forge
pixelmon requires the forge instead of normal patching
Yes, otherwise the mod will not work correctly.
No, Minecraft Forge is not illegal! That is why many people still use mods.
There are many tools such as Modloader and Minecraft Forge that allow different mods work together.
You need to install Minecraft Forge in order for many mods to work. Look up a YouTube tutorial to find out how to install Forge.
Minecraft Forge 1.7.2 will not be realeased until early 2014, as it requires many code changes.
As of the newest forge, no.