For quite a while I've messed around with an old freeware Windows program called Sqirlz Morph. If anyone's really interested I could go into more detail about how to get started with it, but for now I'll share a couple of Hello! Project morphs I've made and put on YouTube.
First, last year when I noticed one of Nakanishi Kana's promo pics for Aa Susukino was quite similar to one from Tachiagirl, I made a morph to show the change over 3 years.
Another that was quite a bit more work was based on the limited edition cover for 13 Colorful Character, where each of the then-10 members of Morning Musume was pictured in an extremely similar pose. So I chopped it up into 10 images and morphed through the lot of them.