Confirmed characters so far with their name beside them, more released tomorrow.
Goku
Piccolo
Krillin
Yamcha
Tien Shinhan
Chaotzu
Nail
King Vegeta
Oozaru King Vegeta
King Cold
Oozaru
Kid Gohan
Yajirobe
Scouter Vegeta
Oozaru Scouter Vegeta
Raditz
Oozaru Raditz
Saibamen
Nappa
Oozaru Nappa
Appule
Cui
Zarbon
Super Zarbon
Dodoria
Captain Ginyu
Recoome
Burter
Jeice
Guldo
1st Form Frieza
2nd Form Frieza
3rd Form Frieza
50% Final Form Frieza
100% Final Form Frieza
Frieza Soldier(Bun in Legend Of The Super Saiya-jin for Super Famicom)
Goku mid
Super Saiyan Goku mid
Vegeta early
Super Saiyan Vegeta early
Demon King Dabura
Fat Buu
Evil Buu
Super Buu
Super Buu(Gotenks absorbed)
Super Buu(Gohan absorbed)
Kid Buu
Babidi
Spopovitch
Majin Vegeta
credit -
Dragon Ball Z Budokai Tenkaichi 3 official site(it's in Japanese)