Apple Shellshock patch for 10.6?
If you don't want to recompile Bash yourself, the folks at TenFourFox (who make a PPC version of Firefox) have compiled a binary that works on OS X 10.4 - 10.9 on both PPC and Intel Macs, and have terminal instructions for installing:

http://tenfourfox.blogspot.com/2014/09/bashing-bash-one-more-time-updated.html

At the time of writing (Sept 30) they've compiled Bash 4.3.27, but this still misses a couple of vulnerabilities that the Apple official patch has also missed.  So it's better than nothing, but you'll want to keep watching for future updates.