The Vocaloid Program is a singing synthesizer application software developed by the Yamaha Corporation that enables users to synthesize singing by just typing in lyrics and melody...
I have read this in a otaku magazine and after that I immediatley search it in youtube(I typed Miku Hatsune) and I was totally amazed in the voice Miku Hatsune...
In real life Miku Hatsune is a long time seiyuu but not very popular after the Vocaloid 2(Oh DARN IT! I forgot the name of the voice behind Miku-san)
and if your not convinced it just try to listen to this song and You will know what I'm trying to say..
Hatsune Miku-Music Box
YouTube - Miku Hatsune Animation PV - Music Box "ã‚ªãƒ«ã‚´ãƒ¼ãƒ«" with Lyrics
and Miku-san is very popular in AMERICA!)I'm not joking,I',m serious!)