MTV Overdrive recently updated it’s site with new videos with some of the English voice casts of Kingdom Hearts 2.

Sanctuary Preview (The Main Theme)
Sora Preview (Haley Joel Osment)
Roxas Preview (Jesse McCartney)
Kairi Preview (Hayden Penettiere)
Riku Preview (David Gallagher) (SPOILER)
Aerith Preview (Mena Suvari)
Hades Preview (James Woods)
Tifa Preview (Lee Cook)

Source: KH Extreme