Grand Line Bout runs off the MUGEN engine and comes with everything pre-packed so all you have to do is click the exe. Register a free acc on the GLB forums and go to the sticky beta3 download thread.
As for emulation, use this wikipedia list.
Every game released on platforms up to the PS2-era has a good and stable emulator (and the Wii too). That includes any for PS2, PS1, Wii, Gamecube, N64, Dreamcast, NDS and anything released on a console existing before 2000. I'm not going to list how to do them, you can probably find that info easily elsewhere.
The gameboy advance game titled "One Piece" is pretty good.
–- Update From New Post Merge ---
The third beta adds Arlong, Trafalgar Law, Rob Lucci, Blueno, Brook, and Foxy, plus a greatly improved Vivi.
I love how u don't link to the 3rd. :sad:
I'm guessing you guys don't allow links to it, since as far as I can tell you can't get it any other way other than to register on the forums. The MUGEN wiki doesn't have a link. I mean it's fine and all that you want people to go on that forum, but just linking outdated versions without the latest is just silly.