The installer wants to know where you want to put Ubuntu 9.04. The default values, shown above, should be perfect. You want to use the entire virtual drive that you created earlier. Click the Forward button. The next screen asks the musical question "Who Are You?"
Enter in your personal information, including your name, a password (twice), and a name for the virtual machine. Make the choice whether you want to type a password to log in, or just have Ubuntu log in automatically, and then click the Forward button. The next screen you see is a summary of all you have just set up. Click the Install button, and the actual Ubuntu installation process takes place.Step 9 -- Update Ubuntu
Once the installation is completed, you'll either be asked to log in with your password, or if you set the installer to log you in automatically, you'll be at the Ubuntu Linux desktop. Since your network connection is already set up, the next thing that will happen is that Ubuntu will check for updates. This is the Ubuntu equivalent of the Software Update in Mac OS X.
By default, Ubuntu wants to download and install all software updates made since the distribution was first shipped. It is recommended to simply click the Install Updates button, which will download and install those updates for you. On my first-generation MacBook Air, this took about a half-hour and required a restart of the virtual machine at completion.Step 10 -- Play!
Once the updates are done, it's time to play with your Ubuntu virtual machine. The user interface is somewhat different from that of Mac OS X, so you'll have to get used to it. You can read Ubuntu's built-in help files by clicking on the question mark icon in the menu bar.
While I will leave the task of learning Ubuntu Linux up to you, one thing I will point out is the Add/Remove Software item under the Applications menu. This is your portal to a large library of software, all of which you can download with a click or two. Think of this as the "App Store" for Linux.
You also have a full office suite installed on your virtual Linux machine. The word processor, spreadsheet, and presentation applications of OpenOffice are all pre-installed with Ubuntu, along with calendar and email functions.
While your Ubuntu Linux virtual machine won't replace your Mac or the applications on it, you can certainly learn a lot more about the Linux world and about virtual machines for free through this tutorial. Have fun!