When Amy was 13 years old, she met Ben Moody, who was fourteen at that time, in a summer camp. Together they formed Evanescence. In 2003 they had a huge break-through with their debut-album 'Fallen'. Over the years, there were several line-up changes and as a result Amy is the last original band member today. At the moment Evanescence is:

Amy Lee - vocals, piano
Terry Balsamo - guitars
Tim McCord - bass
Troy McLawhorn - guitars
Will Hunt - drums

You can find a detailed biography here:
http://evanescence.amy-lee.de

'Broken' was originally supposed to be recorded with Amy's voice but due to a misunderstanding it never worked out. Therefore Seether released their album 'Disclaimer' without Amy's contribution. In 2004 the song was re-recorded - with Amy's voice.
 

At the end of 2006 Korn had a MTV unplugged concert. They asked Amy to come and perform "Freak on A Leash" with them. You can watch their performance here:
 

In 2007 at Coke Fest in South Africa, Amy had the chance to perform one of her favorite songs "Epiphany" with Staind. Here are two videos:

At the concert in Providence, RI on the 4th of April, 2007 Amy came onstage during Finger Eleven's show to perform "One Thing". Here's a video of the performance:

Some time ago another Wind Up band called Big Dismal released an album called 'Believe'. The album features a song called "Missing You" to which Amy contributed. You can only hear her in the background.
 

Amy is featured on two songs of David Hodges (ex-Evanescence, Trading Yesterday).
The songs are called "Breathe" and "Fall Into You" and were released on a church soundtrack. It's not available anymore.

Amy wrote two songs for the Chronicles of Narnia soundtrack. Unfortunately, they were refused. Apparently her music was "too dark and epic". The intro of 'Good Enough' was originally written for the Chronicles of Narnia soundtrack.

Amy's name appears in the liner notes.