https://code.google.com/p/adb-fastboot-install/
Package containing the adb and fastboot binaries and a handful of simple shell scripts to drop them into the appropriate places on mac / linux. Nice.
http://forum.xda-developers.com/showthread.php?t=883032
Really useful guide on how to unock and root the Nexus S. Easy enough to follow, and it actually works!
