This is the best one that I know of for text to speech is
http://text-to-speech.imtranslator.net/
It has a variety of voices and you can control the speed.
The Japanese and Korean sound pretty decent to me, not like a native speaker but pretty good.
EDIT: played around with it a bit today and discovered that it will skip words that begin with '대','저' or '가', there's probably other holes in it too.