If you're posting answers to exercises and want to share them publicly, this is the place.

Scheme

• http://eli.thegreenplace.net/category/programming/lisp/sicp/
• http://github.com/emkay/sicp-exercises/tree/master
• http://github.com/llimllib/personal_code/tree/master/lisp/sicp
• http://github.com/chrisconley/sicp-exercises/tree/master
• http://github.com/pufuwozu/sicp-exercises/tree/master
• http://github.com/judofyr/random/tree/master/sicp
• http://inimino.org/~inimino/projects/2009/SICP/

There is also a wiki for sharing and discussing answers (in Scheme or any other language) which we are adding to as we go:

• http://inimino.org/SICP-wiki/doku.php

Haskell

• http://github.com/llimllib/personal_code/tree/master/haskell/sicp 

Clojure

• http://github.com/burke/sicp-clojure/tree/master
• http://github.com/jamie/sicp/tree/master 

Other