Been awhile since I posted here, huh? Anyway I come here with a question. My freind has told me about this matria called Omega weapon. Supposely what it was to do was summon a monster called Omega(Summon matria?). You could get it by getting all the matria in the game and mastering it. Due to a glich in the game instead what it does is revive Aeris. When he first told me this I just dismissed it off but, then I had another freind back it up. Have you heard of it? Is it true?

No, it's an old rumor that was started by Ben Lansing. He claimed to be an old employee of Square's during the creation of FFVII. He claimed that SE had a way of reviving Aerith that was left out of the final game. There's several variations of this revival method, and the Omega weapon is one of them. You can find out more about it here:

Ben Lansing's Original Aeris Revival Rumor
Final Fantasy VII Rumors
Aeris's Revival Method
"Aeris's Revival" + "Omega Weapon"

The most obvious thing about Omega Weapon is that it's not even a Weapon in FFVII. It's a Weapon in FFVIII. ;)