Sharing data between Mac OS X and Linux is easy if you are using Parallels Desktop or VMWare Fusion or any other virtualization software. However, if you prefer pushing the pedal to the metal, so to speak, there is no other option but to multi-boot your computer. Unfortunately, sharing a partition between systems is quite tricky and more often than not, the default file system for the partition is FAT16/FAT32. Yeah, I know it sucks but hey, at least it is more universal. :)

I know that there are solutions that will make other file systems accessible as read/write on multiple operating systems but since I am not interested in Windows, I'd rather one that gives me access on Linux and Mac OS X. This is where this tutorial comes in. The bottom line is, use HFS+ as your shared partition (remember, not the journaled version, just the plain vanilla one) and may or may not need a kernel re-build. Good luck!