Dual Booting two linux distros
 

Whenever I pose a question on dual booting two Linux distros every answer assumes I am using Windows. I am not.
I currently have a Linux only dedicated computer which currently has K/Ubuntu installed on a ext3 partition that uses the whole hard drive.
I would like to install another distro, preferably a Red Hat or Fedora core distro or both.
My question is what is the best way to do this.
Can I repartition and install the other on it or would I be better off reformatting, creating several primary partitions and one swap then install each distro.
I want to do this so I can learn more about the different Linux bases.
System is an AMD 2000, 512 meg mem, 80 gig drive. All hardware currently works with Ubuntu.
Any help will be appreciated.

What is your current partition scheme?

i'd go with that.

i triple boot xp, slackware 11, and ubuntu 6.10. i installed xp, then slackware, and finally ubuntu, so i could allow ubuntu to automagically handle the config of grub.

Current setup
 

Two partitions Primary and swap. Ubuntu on primary. KDE also installed. Can choose between Gnome and KDE
Interesting about Ubuntu last. Be handy if it took out pain of editing Grub.

it should. from what i've experienced, ubuntu does a good job automatically including already installed os'es in grub so you won't have to edit grub after the install is complete. however, if you choose to use other kernels on another distro then you'll need to edit grub from ubuntu.