I got an Ibook G3 (Dual USB) from a friend.It has Mac OS X 10.1.5 installed.
But also Xubuntu Linux.(Dual Boot)
I want to install Mac OS 10.3 and remove Xubuntu.
How can I do that? I see that the Hard Drive has 3-4 partitions.
I inserted Panther CD but don't understand how can I remove all partitions.
You see I have never used Mac before.
Can somebody explain to me with simple words what should I do?

What you should do:

Insert the Panther disc and boot from it
Go into Disk Utility and format all partitions as Mac OS Extended (Journaled)
Choose one partition to install OS X on
Go into the Panther installer, and continue, continue until you reach the "Select Destination" screen
Choose the partition that you want to install OS X on and install
If you get Panther working, then use some partition program to merge all the partitions together into a single partition OR just leave the partitions alone and use them for data, etc.

I haven't tested this before, just comes of knowledge so no guarantees it will work.

"Go into Disk Utility and format all partitions as Mac OS Extended (Journaled)"

How do I do that?Simply click Erase on every partition?

Isn't there any simple way I can format all hard drive and partitions and have ONE hard drive?

Hmm...maybe

Maybe go into Disk Utility and choose your physical hard drive on the left, go to the Partition tab, set the Volume Scheme to 1 partition and partition. Then just erase that single volume and format it as Mac OS Extended (Journaled).

That could work but I'm not sure, you'll just have to try and see

One problem is that when I open Disk Utility although it shows 4 partitions,they are grey.I mean when click on them there is no information and the Erase button isn't clickable.

Just click the name of the hard drive, not each individual partition. Then click erase. :/

Oh, I didn't knew I can do that. Thanks.

I'm amazed Apple didnt update Disk Utility with Leopard. Its great software, but the interface is very hard to understand for a newbie.