Ruby
http://github.com/fauna/memcached/tree/master
Perl
http://code.google.com/p/perllibmemcached/
Python
http://code.google.com/p/python-libmemcached/
http://pypi.python.org/pypi/pylibmc
PHP
http://pecl.php.net/package/memcached
(In Japanese) http://labs.gree.jp/Top/OpenSource/libmemcached.html

MySQL
Memcached Functions for MySQL
Postgres
PgMemcache
Windows Version
https://code.launchpad.net/~mattn/libmemcached/libmemcached-win32