yah 15th is the start of part 2, but im pretty sure part 1 ended after sasuke ran away with orichimaru and ect ect.
"An announcement in issue #52 of Weekly Shonen Jump has confirmed that the fillers will end in early 2007. After the series moves back into manga-adapted episodes, it will be renamed Naruto: Shippūden (疾風伝, Naruto: Shippūden? lit. Hurricane Chronicles). The new series is set to premiere on February 15, 2007."