http://www.danga.com/memcached/
I guess there's still a lot to be documented, like the memory allocation scheme and the protocol, but it's a start.
Any PHP or Java programmers want to contribute APIs? The Perl module is miniscule. I'm sure a good PHP or Java person could whip one out in no time.... Evan, you could do your languages like Python, Ruby, Haskell, OCaml, etc... :-)