Yaron, you have to run tune2fs to add journaling support for that partition.
Then you should be able to mount the partition as ext3.  You should definitely
run fsck.ext2 on that partition before you run tune2fs.  Clean everything up
first.  Then, run tune2fs to add journalling.  Then remount the partition as
ext3.

NAME
       tune2fs - adjust tunable filesystem parameters on second extended filesystems

SYNOPSIS
       tune2fs  [  -l  ] [ -c max-mount-counts ] [ -e errors-behavior ] [ -i interval-between-
       checks ] [ -j ] [ -J journal-options ] [ -m reserved-blocks-percentage ] [ -r reserved-
       blocks-count  ]  [ -s sparse-super-flag ] [ -u user ] [ -g group ] [ -C mount-count ] [
       -L volume-name ] [ -M last-mounted-directory ] [ -O [^]feature[,...]  ]  [  -U  UUID  ]
       device


HINT: Make sure you set your fs types in /etc/fstab to "auto".  That way, you
can still mount the parititons as ext2 on a kernel that doesn't support ext3.
(Very nice for recovery operations.)

-- 
Chad Walstrom <chewie at wookimus.net>                 | a.k.a. ^chewie
http://www.wookimus.net/                            | s.k.a. gunnarr
Get my public key, ICQ#, etc.  Send email w/the Subject: "get help"