Hot damn! An implementation of Blocks for pre-10.6 operating systems, this time including installers, compiler support, and runtimes for both OS X 10.5 and iPhone OS 3.0.
I say again: Hot Damn!
The only downside I can see so far is that they’re not using github to host the source code :oP
For those with interest in helping out, there’s a forum set up at Google Groups for that express purpose.