JoJo's Bizarre Copypasta on how/where to read. Araki Compilation Mediafire with all of Jojo and other Araki works: http://www.mediafire.com/ArakiCollection
Parts 1-3 are on mangatraders.com or here: Part 1 - Phantom Blood http://www.megaupload.com/?d=1FDBBNW8
Part 2 - Battle Tendency http://www.megaupload.com/?d=QEZ28TUR
Part 3 has an official English release from Viz, if you don't like the scans, buy that, or slap the text onto better raws yourself!
Part 3 - Stardust Crusaders http://www.megaupload.com/?d=NCGQR155
Part 4's translation is just bad(and wonderful), it's being redone(slowly) here: http://donebetterelsewhere.blogspot.com/ You'll have to stick with the wonderful Duwang edition for the parts that haven't been redone yet.
Part 5 is also on mangatraders. About it's translation, it's pretty bad, just more gramatically correct than part 4's, so it doesn't seem as bad. JoJoProject is starting to retranslate/scan it. Redone volumes will be with the 6 and 7 scanlations.