There's some more recent Photoshop tutorials by Julienne Kost that are good, especially for those slow to digest CS4 features. First, there's Top 10 little-known features in Photoshop CS4.
For more on working with scaling, alignment, and auto-blending, check out Photoshop Works for You. In her latest tutorial, Julieanne Kost shows you how to open 3 images at once in Photoshop and then easily arrange them into a triptych. This sort of thing is much easier now: