I have read that it is good practice to separate the OS and data onto separate partitions, the problem is however that most of the sources that I found don't really explain how to do this.

Would someone go into detail and explain how to do this? I already have my drive partitioned and formated with ext3. If i wanted to move say /home to the "data partition" what are the steps?

0. backup (or if you're really 'brave', skip this step)
1. create and format the partition that you want to be the new 'home'
2. mount it - say something like: mount /dev/hdb1 /mnt
3. copy the contents of 'home': cp -a /home/* /mnt/.
4. unmount it (not really necessary, but don't be sloppy): umount /mnt
5. remount it at /home: mount /dev/hdb1 /home
6. make sure everything is OK
7. unmount it - make very very sure you've unmounted it
8. nuke the old home to free disk space: rm -rf /home/*
9. edit /etc/fstab to make sure it's automounted on boot - the entry would be something like:
/dev/hdb1 /home ext3 defaults,errors=remount-ro 0 2
That says mount /dev/hdb1 at the point /home with the 'ext3' filesystem using the default options, and if there's an error remount it as read-only. The 0 and 2 have to do with filesystem checks - you may have noticed that the root file system has 0 1 and all removable storage such as CDROM have 0 0. For more info on those strange numbers, read the fstab manual.

10. Remount one final time to make sure you got the fstab entry right:
mount /home
(since there is an fstab entry, mount will do the right thing - if you didn't make a mistake)

And that's it - every time you reboot, 'home' will be that shiny new partition.

Thanks for the quick reply. I mistyped I don't have a separate partition but rather a raid 1 configuration (with 2 hard disk) that i want to put the /home directory on. I understand your response still though, but i have one question.

If the disk in the RAID 1 config are set to 'Linux autodetect' how should i put that into the fstab file where you have the ext3 file?