Time to get this area populated! Lets start off with a nifty guide I found over on ffxivnfo.com! They have a well written guide on Materia melding and what you have to do to gain the ability to do so. As a side note, you will have to have a crafting class that is high enough in level to meld materia to certain pieces of equipment. It's a double whammy but it's how they get you more involved in the game. I currently can do most armor materia melding except leather but I'm working on it!
Even if equipment is bound to someone, you can meld materia to their gear for them in the trade window I believe but I have yet to try it.