I had issues with the torrent version (wouldn't get past Adobe AIR part of install, even though I already had it and re-installed it), so I tried the rapidshare link (#1). Worked like a charm.
It doesn't run as well as natively in WinXP, which is to be expected. Probably 10-19 FPS is the norm on Low/Auto settings, which actually is fine, but when multiple summoners are in an area battling, I can drop into 5-8 FPS and I had a lag death or three.
I guess it's decent enough for a rare game in OSX, but real games will have to stick in WinXP where I get better FPS in all scenarios.