There's an easier way - when you type a reply there's all kinds of little options just above where you type in. There's a drop down box that says [FONT] and another to its right that says [Size] and one to it's right that says [Color] <--- (Why is that spelled American style??).

So, type in your bit, then highlight it with your mouse, then change one of them. Each time you change one, it will do the typing thingy like what Chuck just said, if you want to make a second change you'll need to highlight it all again.