How would you dual-boot Ubuntu 12.04 on a MacBook Pro with the following specs: 13", 750GB hard drive, Intel Core-i7 processor, with 8GB RAM.
rEFIt is the best way to allow dual-booting on a Mac. I use it to boot Ubuntu from a partition on my external drive, and it works perfectly. Be sure to back up your hard drive before proceeding.
Install rEFIt and make sure it is working (you should get a boot chooser on startup) Use Bootcamp or Disk Utility to create a partition at the end of the disc. Don’t worry about what format, just make it the size you want for Ubuntu and your swap partition. If you you are using OS X Lion which comes with Bootcamp 4.0 you will need to use the Disk Utility. Boot Camp 4.0 will only allow you to resize if you provide a Windows 7 installation disk. Boot the Ubuntu desktop CD, and select "Try Ubuntu. Start the partition editor (gparted) under System -> Adminstration. Use gparted to delete the partition you just made in OS X. It should be the last partition on the disc and follows after the HFS+ partition (OS X). Deleting it will leave an area called unallocated. This is free space, and exactly what you want. Use gparted to manually partition the space on your drive for Ubuntu. First create a SWAP area of about 1GB. Then the rest of the unallocated area format as EXT4. Apply changes and take note the label of the EXT4 partition such as /dev/sda3.
Start the Ubuntu Installer from the desktop icon. When prompted, choose to manually partition. Select the EXT4 partition and click change. Select to use the space as EXT4 and root (/) as the mount point. You will also want to check the box to format the partition. Reboot when done with the install, and in the rEFIt menu, choose the partition tool. It will attempt to sync the partition tables on your disk. Then SHUTDOWN the computer (not reboot), and start it again. You should be able to boot to Ubuntu now. If it seems to freeze on the tux logo, completely shutdown again and try one more time.
This is a summary of a process described by the detailed how-to process here: https://help.ubuntu.com/community/MactelSupportTeam/AppleIntelInstallation#Detailed_How-To