Newbie Mac tip: Mac OS X 10.3 (Panther) includes a nifty development suite and all the SDK's you'd need for OS X application development, and even porting X11 apps from Linux/Unix. In the Mac OS X installation that came with my PowerBook, the developer tools were not installed, but the installer was on the hard drive. To install, use the Finder to browse to /Applications/Installers/Developer Tools and double-click on Developer.mpkg. All the developer stuff will be installed to /Developer, with Xcode and the Interface Builder in /Developer/Applications.