To know about Vocaloid Singing Synthesis technology, see this page (introduction of English Vocaloid: LOLA):
http://www.zero-g.co.uk/index.cfm?articleid=800
Vocaloid2: Hatsune Miku official page (includes three demosongs):
http://www.crypton.co.jp/mp/pages/pr...aloid/cv01.jsp
Other superb Vocaloid songs on YouTube:
Uninstall (by Vocaloid: Meiko):
http://www.youtube.com/watch?v=2yDSbFe62E4
True My Heart (by Vocaloid2: Hatsune Miku):
http://www.youtube.com/watch?v=5XV_zTMlk18