Gear Thingy --> Preferences --> Advanced, Check "Show develop in menu bar" Then Page Icon --> Develop --> Show Web Inspector
I'm using Safari 5.0.4 but it should be the same. i'll download .0.5 and check, to be sure though.
Wow, i totally forgot to edit this. Anywho, i downloaded 5.0.5 and it still works. Click the Gear, then click preferences, then Advanced, then Check "Show develop in menu bar", close that out, then click the page icon, then develop, then "show error console"