I find that folks always get frustrated with moving images between events in iPhoto. Of course, there are tons of ways you could do that, but the method I use is pretty simple. To try it out, first you'll go through your iPhoto Library and flag pictures that you want to add to a particular event. You can do that by clicking each one to select it (or holding down Command and clicking to select more than one at a time) and then choosing Photos > Flag Photo or pressing the keyboard shortcut Command-Period.
If you're going one by one, you can also click on the tiny flag that appears when you hover over a photo to do the same thing.
Once you've got a whole bunch of images flagged, it's really really REALLY simple to put them where you want them. Just go to your events, click on the one you want to add your flagged photos to, and choose Events > Add Flagged Photos To Selected Event.
Then iPhoto'll pull the images out of whatever events they happened to belong to and into the one you've specified. And as you'll note from the above screenshot, if you want to make a new event to put your flagged photos in instead, you could select Events > Create Event From Flagged Photos. Nifty stuff, and easy, too!
When you're finished with your current crop of photos to be moved, select them and choose Photos > Unflag Photos (Command-Period again) to clear out those flags. You could also select the Flagged album from iPhoto's left-hand list and then click on Clear Flagged.
So what say you, TMO readers? Do you have a method for moving photos between events that you like better than this?