On Mac if you want to access ext3/etx2 filesystems, which are used by Linux systems, you will find lots of links on net but all are pretty outdate and they don’t work for Lion. So, here is the updated version, which works. At least for me.
You will need two softwares:-
OSXFuse – OSXFUSE-2.4.2.dmg
Fuse-ext2 – fuse-ext2-0.0.7.dmg
Download and install them in the sequence shown above.
Fuse-ext2 needs MacFuse to run, but this is no longer maintained and does not work on Lion. OSXFuse is the next generation MacFuse, but Fuse-ext2 is not meant to work with this. Fortunately OSXFuse includes “MacFUSE Compatibility Layer”. Just make sure to select this option when installing OSXFuse and you are good to go.
When both of them are installed, then try plugging in ext3 or etx2 partitioned disk and they should get automatically mounted, just like any other disk. Note, after installing them you may or may not need to restart your system.
PS. You will be able to read the disks but not write to it. As of now write option is not reliable.