Was excited to know that microsoft provide a good api of translation, and even text to speech support.
But after dig in a while, I find out that they do have a limit of 4 million characters monthly, and up to 2m daily limit. Need more than the quota, got to buy from them at a price like $10 per 10m characters.
This limitation has no problem on some small usage, but if you are a webmaster running on cheap sites and want to add the static translation support for seo, would really stuck on this. This makes the microsoft translation api useless for those webmasters.
So be careful, when you are into some stuff appears to be free.
This is where the translator: http://www.microsofttranslator.com/tools/