Partitioning to install Ubuntu 11.04

The newest Ubuntu installer attempts to repartition without destroying the existing partition. You could TRY doing this.

Alternatively, use your OS X installer DVD's Disk Utility to simply repartition the drive however you want - I'd recommend using at least 30GB for OS X, then a minimum of 15GB for Ubuntu (especially if you install a lot of applications and such), with a partition at the end for data and whatnot.

If you don't plan on using Ubuntu very much, though, I'd recommend sticking with using a virtual machine instead of a native installation.

What is "messed up" with your VMs?

 

Do your partitioning in Diskutility like ubuntu recommends and make sure that you name it something that you will recognize. Ubuntu's installer will reformat that partition anyways so don't worry about it.

You don't exactly "install" an iso into a partition like you do with a VM. You burn that iso to a disk and then boot into that disk, either holding option and selecting the disc during startup, or holding "c" during startup. Then you proceed with your install as you would normally. Ubuntu's is a guided process so it's pretty easy. Make sure you install into the right partition and do a backup beforehand anyways, just in case.