If your talking about shippuden (most likely). I would say quite a while. At the moment the company who dubs naruto (Viz media) are working on box set fifteen(up to epidsode 192-ish). Everything takes quite a while to get out there due to royalties to be paid to the specific people ect ect. So i would guess that we will get to episode 248 at the end of 2013 or the beginning of 2014. As of yet we are up to episode 154 (twelth box set) of the dubbed (thats out to buy and watch) so ... yeh . Its gonna be a while dude !!