Dattebayo.com hosts the best seeded naruto torrents I've found on the internet.
You can get almost all the episodes with English subs(subtitles) including the Naruto movies. Subs are available in a variety of languages like Portuguese, Brazilian and even French.
You can also try other sites like torrentz.com or youtorrent.com if you need some of the older episodes.
You can download ".torrent" file for the latest episode from the Naruto page on this site.
For all other episodes go to any of the above torrent sites. Download ".torrent" files and load them into your BitTorrent client and start downloading/leeching.
I would prefer µTorrent which is easy to use, fast and needs very few system resources. A quick comparison of BitTorrent clients here - decide for yourselves.
I'm trying to compile a real good list of Naruto resources available on the web.
Like Low quality smaller episodes available for people with lower bandwidths, Episodes for direct downloads and Mobisodes(Episodes for mobile and iPod viewing).
Please feel free to email them to me at admin@greysquare.org so that I may include them here. You will be given due credit.
BitTorrent is by far the best method to obtain Naruto episodes, any TV episode for that matter, unless you know sites which offer direct downloads of high quality episodes.
For basics of BitTorrent usage try Google'ing and finding resources from sites like Wikipedia.