AdbFuseFS

This FUSE filesystem let's you mount your internal device memory. Download distribution tarball at: http://www.mediafire.com/?pxkkbm5hmqap9ya , then ./configure & make & make install. First connect your phone (or emulator). After that you must make sure the adb server is running, so try some eclipse deployment or just run 'adb shell'. You can mount your phone by 'adbfusefs -s <mountpoint>'. If you experience any problems, try runing adbfusefs with -d option.
Current gotchas:

• when file is opened, it is copied to a temporary directory. Just opening  the /system/ directory in nautilus can take quite a long time, since it tries to fetch previews for all the APKs there

• advanced file operations (readlink,mv,rm...) are implemented by issuing shell commands. This is only tested with busybox-enabled phone. 
• Does not call adb command. Adb need not be on your phone, but adb server has to be started. Adbfusefs  uses its sync service directly.

And for those lazy, here comes 32-bit linux binary.