Just wanted to make a note about this.
If you're on Snow Leopard and tried to install ext2fsx (which will result in failure), attempting to use ext2-fuse may result in:
fuse-ext2: version:'0.0.7', fuse_version:'27' [main (../../fuse-ext2/fuse-ext2.c:324)]
fuse-ext2: enter [do_probe (../../fuse-ext2/do_probe.c:30)]
fuse-ext2: Error while trying to open /dev/disk1s1 (rc=16) [do_probe (../../fuse-ext2/do_probe.c:34)]
fuse-ext2: Probe failed [main (../../fuse-ext2/fuse-ext2.c:340)]
Although the installer of ext2fsx failed, it may not roll back successfully. A call to
sudo dmesg | tail might show something similar after pluging in the device:
ext2fs: registering sysctl 'e2fs' with OID 61267
ext2fs: registering sysctl 'dircheck' with OID 1
ext2fs: registering sysctl 'lookcacheinval' with OID 2
ext2fs: reading superblock from block 2, with size 1024 and offset 0
ext2fs: dir_index feature detected - write support disabled
EXT2-fs DEBUG (/Users/brian/Projects/Sourceforge/ext2tiger/src/gnu/ext2fs/ext2_vfsops.c, 1465): ext2_vget:Returning Error! (2)
EXT2-fs DEBUG (/Users/brian/Projects/Sourceforge/ext2tiger/src/gnu/ext2fs/ext2_vfsops.c, 1663): ext2_root:Returning Error! (2)
Notice that even though ext2fsx failed, it's still attempting to access the drive.
To fix this, run ext2fsx's uninstall script. You can then use ext2-fuse without any hassle.