From the Characters Selection menu tap the sequence:
[X], [X], [Y], [Y], [X], [Y], [X], [Y], [X], [X]: Nine Tails Naruto

At The Character Select Screen, Enter The Following Codes:
[Up], [Down], [X], [X], [Y], [X], [Y], [B]: Unlock Sasuke

Complete each achievement to get the allotted gamerscore.
Academy Graduate (15): Reach the Graduate rank online
Card Collector (40): Find all of the ninja cards
Chunin (20): Reach the Chunin rank online
Delivery boy (10): Complete all delivery missions with Shikamaru
Don't be shy (5): Play a match online
Fisherman (15): Win a gold medal in any fishing game
Genin (15): Reach the Genin rank online
Gifted eye (15): Complete all hide and seek missions with Neji
Gold collector (35): Collect 50% of the gold coins
Gold digger (50): Collect all of the gold coins
Hokage (0): Reach Hokage rank online
Jonin (30): Reach the Jonin rank online
King of the iron fist (5): Win a fight using a killer combo
Legendary fisherman (25): Win all of the fishing gold medals
My taijutsu coach (20): Learn all of the combos in the Dojo
Naruto Raving Ninja (25): Win all of the gold medals in the Tanzaku festival games
Naruto's creed (25): Complete all of the bounty hunter missions
Pervy Nation (20): Make all of the Lovelorn Villagers happy by performing the sexy jutsu
Save the Trees (15): Win an online match without performing a substitution
Solo champion (25): Win a tournament in solo mode
Team champion (25): win a tournament in tag fighting
The last chip is the best (20): Complete all gathering missions with Choji
Top dog (20): Complete all races with Kiba
Untouchable (20): Win a fight without losing any health
Way of the tree (20): Win a gold medal in a Tree Action Sequence
World's fastest Ninja (15): Win all of the gold medals in the Tree Action Sequences

Hokage's Arena: Beat Tag Tournament Mode
Temple Courtyard: Beat Solo Tournament Mode

ANBU Itachi: Complete Sasuke's 2nd Labyrinth in story mode
Gaara: Defeat Gaara in Rock Lee's flashback in story mode
Green Suit Naruto: Find the flowers mission for Guy in story mode
Itachi Uchiha: Beat Itachi in story mode
Jirobo: Complete the fight against Jirobo in story mode
Kabuto: Beat Kabuto in Story Mode
Kidomaru: Beat Kidomaru in Story mode
Kimimaro: Defeat Kimimaro as Naruto in story mode
Kisame: Survive Kisame's attacks in story mode
New Sasuke: Complete the fight against Sasuke in story mode
Nine-Tailed Naruto: Transform into Fox Naruto in story mode
Rock Lee: Defeat Kimimaro as Rock Lee in story mode
Sakon: Beat The Sound Four as Sasuke in story mode
Tayuya: Beat Sakon in story mode
Temari: Complete the against Tayuya in story mode
Tsunade: Make Tsunade Hokage in story mode