I've now installed Wizard101 successfully on three MAC's (two Macbooks and one MacBook Air) Check out www.codeweavers.com There's an app called CrossOver Games. You'll need to purchase the app after the 7 day trial is over, but it's reasonable. After downloading and installing CrossOver Games, you can install Wizard101
It runs fine. The graphics have a few minor glitches but it's totally playable. Wizard101 is supported by Codeweavers so it's bound to get better over time
I used to play W101 on my mac (untill I spilled a smoothie on it, but that's a different story). I had downloded windows on it, windows costed like, $80, but it was worth it.