The slide layouts provided by the previous version of PowerPoint 2007 are not allowed to be defined by the user, and PowerPoint 2007 now allows you to customize the specific slide layouts you want. To add a new custom slide layout, you must first switch to slide master view, add a new slide layout, attach the object you want, and then save as a template file.
First, click the View tab in the Ribbon, and then click the Slide Master button in the Presentation View Options group.
When you go to slide master view, the left pane of the screen shows the default slide master and layout thumbnails, click the thumbnail for the layout you want to add, and then click the Insert Layout button in the Edit Master option group.
After you add a new slide, you can set up the various components you want to add on this slide and quickly create a new custom slide layout. Click the Insert Placeholder button in the Master Layout Options group.
Tip: In the Master Layout option group, there are two check box options for the title and footer, and you can choose whether you want to display or remove slide title text, date, page number, and so on in the slide layout.
Next, select the configuration object that you want to use from the Drop-down menu and drag the desired placeholder directly on the layout of the slide with the mouse.
Finally, save it as a "PowerPoint template" (. potx). You can apply a custom slide layout later as long as you create a new slide with the presentation template.