Snow Leopard has started the process of deprecating Carbon, the API that the current OS X devdraw uses. As of Snow Leopard, it can only be used in 32-bit binaries. Some future release will remove support entirely.
Jeff Sickel has started Cocoa support, which requires working in Objective C. It can put bits on the screen but doesn't receive mouse events. It can handle resize after a click in the window. Improvements welcome.