Many switchers to Mac OS X have the same question: "how can I customize my application toolbars?" While this is fairly straightforward in Windows, Mac OS X makes it much easier. Just open the customization menu by right-clicking (if you have a one-button mouse you can control + click) on the toolbar, then select "Customize..."
When you do this, you are presented with a dialog box that "rolls down" to display all of the items that you can add. Just drag the ones you want to the toolbar. If you find you don't want a certain toolbar item, just open the customize panel again and drag the item off the menu bar.