Does anyone know where I can find free piano and/or guitar sheet music?

I’m mainly looking for “Back To Black” by Amy Winehouse, “Ordinary People” by John Legend, “Tell Me ‘Bout It” by Joss Stone & “Smells Like Teen Spirit” by Nirvana. Any solid answers and/or suggestions would really be appreciated. Thanks (P.S. I’ve tried www.ultimate-guitar.com & freesheetmusicplus.com, but neither of them provided me with the aforementioned music sheets…well, maybe Nirvana, but that’s it)

Try http://www.sheetmusicfox.com
They have a great variety of free sheet music, and a very powerful sheet music search engine.

‘About A Girl’ Guitar Lesson – Nirvana (guitarteacher.com)

Nirvana: 30 Note-for-Note Guitar Transcriptions, CD-ROM Sheet Music $12.22 Print sheet music from your computer! This innovative CD-ROM for PC or Mac contains 30 of Nirvana’s absolute best transcribed note-for-note for guitar with tab – over 140 pages of music! Includes: About a Girl * All Apologies * Aneurysm * Been a Son * Blew * Breed * Come As You Are * Downer * Drain You * Dumb * Floyd the Barber * Heart Shaped Box * In Bloom * Lithium * Lounge Act * The Man Who Sol…

Smells Like Teen Spirit (Guitar sheet music with notes and tab, Sheet Music) $4.99 SMELLS LIKE TEEN SPIRIT Series: Guitar Sheet TAB Artist: Nirvana Guitar sheet music with notes and tab….

Nirvana – From the Muddy Banks of the Wishkah* (Guitar Recorded Version) $12.90 Matching folio to the live album featuring 16 songs, including: Breed + Heart Shaped Box + (New Wave) Polly + Smells Like Teen Spirit + Spank Thru + and more….