Okay, I read the books just recently so I will spoil it and tell you how it all happens if you do so care to read.
Spoiler:
Frodo goes nuts (the ring posesses him) and he puts the ring on while standing above the fires of Mt. Doom to get passed Sam-Wise Gamgee who is intent on making sure Frodo get's rid of the ring. Frodo knocks Sam down and then Frodo runs into Gollum who bites off Frodo's finger in a scuffle and steals the ring with the finger still in it. Gollum loses his balance and falls into the firey casm from whence the ring was forged.
MORONS AND INSOLENT FOOLS do you not understand my question I am obbsed with lotr yes i have read every book at least twice and seen the movies a 10000 times i saw the second one in the theatre 3 times on opening night then 5 more times throughout the week i was asking if you knew how it was destroyed i knew before i ask the question I just wanted to see someof your alls answers