I want to install Ubuntu 10.10 on my Macmini first gen(Snow Leopard),my iMac G3(Tiger), or my PowerBook G4(Tiger). But i still want my Mac OS X on it. I can't use the disk utility to partition my drives. Even though my macmini runs Snow Leopard the disk utillity says that I need 10 GB of free space even though i have way more then that. I tried using the Ubuntu 10.10 partition table to partition my computer(s) with it. But I can't figure out how to use it. Please Help!!!
Is there any reason why you go with 10.10 instead of 12.10 or 12.04 LTS?
When installing Ubuntu, choose manual partitioning and set 3 partitions for your Ubuntu. Make first boot point
Be sure that you backup your data from MAC as you need to format whole drive if you didn't left unpartitioned space on drive.
The "free space" you've got now is within your OS X partition. As such, it can't be used to hold a new OS -- for the most part, every OS requires its own partition (or sometimes multiple partitions, as 10robinho has suggested). Thus, you need to shrink your existing OS X partition (or perhaps a data partition, if you've got a separate data partition) to make room for Linux. You can do this with OS X's Disk Utility, but be aware that resizing partitions is inherently dangerous, so it's best to back up your important data before you proceed.
There are numerous online guides that can help you set up an OS X/Linux dual-boot configuration. The only one whose URL I have handy is my own, at http://www.rodsbooks.com/ubuntu-efi/index.html. A Web search will turn up more.
I'm not familiar with the details of installing Ubuntu on a PowerPC system, so I can't comment on any specifics you'd encounter with that. A G3 system, in particular, is likely to be quite slow with a modern Linux installation.