How to divide a partition into two parts?

[devils casper]

/dev/sda3 will be an Extended partition and you can use it for /home. Extended Partition is like a container only. It contains Logical Partitions. Your /home partition will be /dev/sda5 and you can create more partitions inside Extended partition.

what will I have to write in the /etc/fstab file?

You have to set new partition as /home in /etc/fstab file.

[Jonathan183]

First I never said resize a live filesystem - and please if you are confused don't confuse others by saying not reccommended when you even don't know what it is spoken about.

I didn't say you did ... I'm sure I have read something somewhere about using loop device for partition resizing but can't remember if that was for a live file system. I am not confused at all about the method which works best for me so I though I would share it (live CD). Just because something may be possible does not mean I would recommend it.
Parted can be used for resizing in some instances, but I still prefer to use a GUI and live CD for this type of operation.

[NewinLinux]

Thank you all for the guidance. I will post here if something goes wrong, although there is almost no chance of going wrong now.

[computerophil]

.... I still prefer to use a GUI and live CD for this type of operation.

So I ask you ("Linux Guru") to read more carefully before giving your commend:
GParted I spoke about is exactly with GUI: it looks like Partition Magic in some way:



I don't know anything easier (it can be intuitively used) and more secure. And to use it from a LiveCD is perfect.