how do I change the highlight color in notes
How do I use different highlight colors within 1 document in pages
iPhoto '11
If you are using Apple's definition of Highlight from the Insert menu, then you can change the Author color from the View menu : Comments & Changes : Author Color menu hierarchy.
If you are using the true word processing definition of Highlight, then it is on the Advanced Options menu : Character Fill Color inkwell, or color globe (chooser).