Here is my partition table from fdisk -l

Disk /dev/hda: 122.9 GB, 122942324736 bytes
255 heads, 63 sectors/track, 14946 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/hda1 * 1 865 6948081 b Win95 FAT32
/dev/hda2 866 14946 113105632+ f Win95 Ext'd (LBA)
/dev/hda5 866 905 321268+ 83 Linux
/dev/hda6 906 2621 13783738+ b Win95 FAT32
/dev/hda7 2622 11221 69079468+ b Win95 FAT32
/dev/hda8 11222 11352 1052226 82 Linux swap
/dev/hda9 11353 14946 28868773+ 83 Linux

/dev/hda9 was where my redhatlinux 9.0 was installed on, but now redhat will not support redhat* no more, but only Fedora Project.
SO i decide to try Mandrakes 9.1 since that's the only dist. i have with me. Once i heard of you could split a extended drive in linux. I know that must be true but how can i split my /dev/hda9 in to /dev/hda9 for redhat and /dev/hda10 for mandrakes?
Also, if i did sucessful repartition it, do i make then share the /boot directory?
Any ideas?

Use Parted or Qtparted to repartition, or resize2fs if you use ext2/ext3.

could u gave me more detail.
I am not a newbie, but still not a powerful user yet.
From my Hardware Browser, it states that my hda9 have 28192 mb and the partition type was ext3.
I was leave my redhatlinux for around 15gb and 13gb for my new mandrakes.
And do before i do it, do i need to defragment my hard drive or is it necessary. because it seems linux doesn't need to defrag.

Well with resize2fs...
You need to have hda9 unmounted, so use a rescue disk or something.
First:
$ resize2fs /dev/hda9 [newsize (in blocks, they're usaully 4kb)]
Now your ext3 filesystem is newsize blocks (<-any size you choose, like 15gb). But your hda9 is still the original size. Resize it with fdisk. Just delete the partition and recreate it. This is the tricky part. If the partition you recreate doesn't start in the same place, it could mess up things. Same thing if you recreate it too small (smaller than newsize). Once the partition is remade, you have free space to make new partitions.

but how can i creat my new mandrake partition?
Do i need to use resize2fs again or i just need to use fdisk to creat a new partition?
Also, how could u tell fdisk to creat a drive which could fill all the rest of the space which was on that drive?

jeese, how many partitions can exist on a standard hard drive?

I guess about 44 usable ones.

Once you resize your partition, you leave unpartitioned space on your hard drive. The Mandrake Linux installation has the nice graphical tool DiskDrake for managing partitions (don't know if you can use that for resizing your ext3 instead of with resize2fs). You can use that to create your Mandrake partitions. Try using cfdisk instead of fdisk when possible. It is easier. In cfdisk, when you choose 'New', the free space on the disk is selected already, but you can change it if you want.