In case people skimmed the previous post...
Wi-Fi sharing of Ethernet doesn't work for WPA2!!!
They took out WEP support, so now the PSP (100+million users) can't connect to a MAC OSX sharing the Ethernet over Wi-Fi. Only option? NO SECURITY.
THIS IS A MAJOR SECURITY RISK! The OSX's WPA2 doesn't work. WEP is taken out, so if you share your Ethernet, EVERYONE can connect, because that is the only way you can share via Wi-Fi (no security).
WEP isn't very effective security...Google "WEP hacking" and see how long it takes to hack a WEP protected network. Not that WPA2 is impregnable, but it's much better.
Leaving users with the option of no security or WPA2 is a weird thing for Apple to do but if you know you don't have a secure Wi-Fi connection you'll hopefully self-filter your websites, with crappy security (e.g. WEP) you may not be so prone to self-filter and that complacency may be what Apple's trying to protect you from. I dunno, but a WPA2-enabled router isn't very expensive (~$50 on Amazon.com).
Do you use hotel, Barnes & Nobles, public library or any other "free" wi-fi? They're typically unsecured (and hackers spoof being a hotel access point as well).