In the event library in iMovie you should be able to see iPhoto videos - click on this, find the video you want to rotate, make sure you select the whole clip and then click and drag it to an existing iMovie event.
Once you've done this, add the iPhoto video into a new or existing project, and with the clip highlighted press the 'C' button on your keyboard, or the clip tool in iMovie, either of which will open a crop window which will have at the top of it a left and right rotate button.
Refer to the following links for more information
Thank you, for the information which was most helpful to me, the newbie I am in performing this new venture on my part.
It is so helpful to have techies like you available to assist newbies especially ones who are very advanced in their years and were not born with a computer brain as the younger generation have been.
Thanks, too, for the Apple Support Links. They are also most helpful.
Back to my project and placing it on our group's website. Now, I feel I am gaining knowledge about making videos and mounting them on a website.
Have a good day!