You will want to save your hard work for sharing and reusing. Select the Save As option (File ’ Save As) and change the type to Design Template (*.pot). When you switch from presentation to template, the list of files showing in the Save in area should change to the location where the rest of the templates reside.
If you used fonts other than the standard ones, be sure to save the fonts with the template. To do this, select Save Options from the Tools drop-down when doing the Save As (this option is not available for templates in PowerPoint 2000 and earlier).
Before sharing this template, use it to create a test presentation with each of the defined color schemes. Starting from scratch, open a new presentation using the template. Type in some dummy text. Verify the text slides look the way you want them to look. Insert a graphic or other style of slide and make sure it also looks the way you want. Insert both title and content slides. Add non-text slides to make sure the graphs, movies and other elements look good on the chosen background.
Check out the notes and handouts pages to make sure they look the way you want them to. Even if you never plan to print notes or handouts from PowerPoint, the users of the templates may want to. You don't want them to do a test print and find out the template's masters don't allow them to print what they need to.
Run the presentation in slide show mode and see it automates and transitions the way you want it to. Have someone else look at the presentation and see what they think of it. Finally, have someone else create a presentation on another computer using the template.
If you find things to change, open the template file, view the master slides (and other elements) and make the changes there. Once you have saved the changes, re-apply the template to the test presentations and test again.
Now that you have created a masterpiece of a template, you can share the template by sending the file to others who need it. However, be warned a template file is not always small. The smallest ones I have created are about 40 KB in size (you can create smaller ones if you use no graphics or effects). Embedding fonts can also increase the size .
40KB doesn't sound very big does it? Well, let's look at that from the other side. If my template has a large graphic in it, plus some music and a couple of fonts, it can become quite large quite quickly. In fact, I changed one template from 50KB to over 900KB, just by adding a sound, two fonts and a picture.) The more you add to a template, the larger the file will be.
If you want to make sure presentations created with your template are identified as yours, go to File ’ Properties and change the information on the Summary tab. Few people will look there for information, so the template should stay marked as yours.