This is a fun tutorial for beginner level users of Illustrator. I am using Illustrator CS2.

First, using your Ellipse Tool, create an elongated ellipse like the one shown below. This is the first petal of our flower.
The Ellipse Tool looks like this:

Next, with the petal selected, click on the Rotate Tool in your tool box.
The Rotate Tool looks like this:

Once you have clicked on the tool icon, hold the Option(mac)/Alt(pc) keyas you move the cursor to the point you want your petals to rotate around and click. You will see the light blue rotation point on your artboard as shown below.

Once you select your rotation point, the Rotation dialogue box will appear.

Select the angle at which you want your petals to rotate around the rotation point (I am using a 30 degree angle) and hit COPY. Do not hit OK as this will simply rotate your original petal rather than adding a new one.

Next, add the rest of your petals by hitting Command(mac)/Control(pc) and D keys as many times as necessary. You can also repeat this step by going to Object > Transform > Transform Again.

Now that you have all your petals in place, create a circle (or a shape of you choice) and place it on top in the center.

There you have your quick and easy flower.

Once you get the hang of the steps, you can get a little more elaborate with your flowers. A few samples of flowers I made using these steps can be seen below.

Have fun with it!