Here's a source where you can download "free" album pages for any year through 2011. Supplements are added, as needed. However, they don't have an image of the stamp:
http://www.philosateleia.com/album/pages/If you want to create your own album pages, MS Word will work, however, I find it easier to use Excel. Sizing of a border around a stamp can be a problem, as many different stamp sizes are out there. Further, if you collect unused stamps, there are some modern self-adhesive stamps (i.e. certain coil stamps) that come with an oversized backing paper, so you must adjust for not only the size of the stamp but for the overall stamp with backing paper. Then you have to consider if you are mounting the stamps with hinges or stamp mounts, the latter of which could require you to increase the size of your borders to accommodate the mount you prefer to use.
Back to your original question about the size of stamps, most announcements of new issues by the US Postal Service give details as to the exact dimensions of the stamp if you want to be exact as to the size, but then you probably want to leave an appropriate margin around the exact size of the stamp to create a visually acceptable album page.
Here's an example of the published details for the recent Gregory Peck stamp. (Note the red arrows that shows the overall stamp size.):
