The OS I am using here is Ubuntu, but it could have been any linux system [Even on some live cd you can find the tool (eg. Ubuntu Destktop install CD)]], and you could even use that [cd or that liveUSB.
This article intends to be concise in showing you how to manage partitions using that tool. You’ll see screenshot using french language, but you would just have to make the mapping between french and english version.
First, get gparted (using Synaptic [see screenshot 1]] or using the [website )
When you start gparted (on Ubuntu it can be reached on System –> Administration –> Gnome Partition Editor ), you reach that screen [see screenshot 2″>1]. Select the disk you want to modify, Then select Unallocated block and partition -].
After modifying what you have to, you can notice «pending operations» . Click on apply. and it should be fine. You partitionned and formatted your disk(s) .
I hope this could help. Feel free to post any comment on improving that article.
 see screenshot 3″>[see screenshot 2
 see screenshot 4
 Be aware that you only did that, you didn’t either mount your partition, nor edit fstab