If you want One Piece episodes up to 298 I recommend Kaizoku Fansubs. http://www.kaizoku-fansubs.com/ They have active torrents, and a good irc channel with a guide on the website.
After that try Yibis. The 1st 2 posts of this topic have links/info for direct downloads and torrents http://www.yibis.com/index.php?topic=1056.0 (may be in a spoiler tag). When you reach the episodes Yibis themselves have subbed I think they have an irc channel to use. For some episodes direct download from a website may be the only way. Kaizoku Fansubs and Yibis are the 2 best One Piece fansub groups this is generally accepted, Yibis in my opinion being a bit more professional overall, and having a friendlier forum.
Just realised this is a very old topic but anyway hopefully my reply will help some fellow One Piece fans or bring in new fans.