Packing for a Safari to Africa requires a bit more thought than many other excursions. You want to see the animals, first of all, which means not dressing in a way that's going to scare them off. Or dressing in a way that will make a hunter want to take shots at you.
This month, Budget Travel put out a great article, Get the Most out of Your African Safari. There's a nice packing list as part of it, including why you need specific items. If you're heading that way soon or are in planning mode, check this one out. It's not a cheap endeavor to take a safari, so don't mess it up by taking the wrong gear and clothing along.