I'm working on updating Xcode project files for FlightGear 0.9.11-pre1. It has been successfully built and is being tested on both Intel and ppc Macs. I'll post the binary package of 0.9.11-pre1right after some test flights (and if there are less critical bugs). If you want to build it yourself, you can download the Xcode project files, patches, and build scripts from the svn repository.
svn co https://macflightgear.svn.sourceforge.net/svnroot/macflightgear/branches/0.9.11-pre1