I have some questions related with Ubuntu. I have an iMac, with OS X Lion and Windows 7 installed. So, can I install Ubuntu alongside Mac and Windows without any problems? Can I resize my Mac's partition later?
Also, my keyboard doesn't seems to work... :/
My iMac is a Late 2009 with 4 GB of RAM.
This sonuds like a good reason to take caution when installing on a Mac.
From https://help.ubuntu.com/community/UEFIBooting
Caution for Mac owners
From Ubuntu 11.04 onwards (x86_64 only), the ISO CD supports UEFI booting and the Ubuntu installer will try to set up the bootloader for (U)EFI boot. But the installer formats the EFI System Partition to FAT16 (even if the filesystem is non-empty) and also uses efibootmgr, therefore Intel Macs may fail to boot due to corrupted firmware. This feature is not recommended on Mac models because it can corrupt the firmware. You will need to reflash the firmware to repair it.
On Macs use only the Mac alternate ISO CD
Mactel support pages, list what works and what dosen't and version used for mac type, https://wiki.ubuntu.com/MactelSupportTeam/CommunityHelpPages
Mac triple boot how-to https://help.ubuntu.com/community/MacBook/TripleBoot
