Edit the font itself? There's no way to do this in Illustrator or Photoshop. If you want to edit the font characters themselves (so that when you type, it's in a whole other font that you can use for other projects), then you need a font creation/editing program -- something like Fontographer, I imagine. But if you mean edit them as paths for a one-time project in Illustrator, convert the type to outlines. To do that, make sure the text is selected, then go to Type > Create Outlines. That features makes the text into letter-shaped vector art that you can do with as you will -- edit the paths, intersect them with other shapes and paths, or whatever. Hope that helps.