I don't know if this is a known issue yet or not, but I was trying
all day to get pyobjc to install on python 2.5.1 and finally tracked
the problem down to the fact that I had the Safari 3 Beta installed.
Downgrading back to Safari 2 fixed the problem but it was really
annoying. You see lots of errors fly by and then get the nebulous
"lipo: cannot determine arch" error, and all the google pages about
that error say that the fix is installing the 10.4u SDK in Xcode,
which of course was already installed.
Going way back through the logs I could see all the WebKit errors and
decided to try rolling back and everything finally worked.
But this really makes me wonder what the status of Leopard support is