That's what XP calls the 'notification area'; before that it was called the 'system tray'.
http://www.helpwithwindows.com/WindowsXP/tune-03.html tells all you can do with it. And that doesn't include making the icons bigger.
So the answer is: "sorry, but it can't be done".
PS. I removed your other post about MS Word. We don't allow unrelated tagline links.
I've looked everywhere but can't find any answer, this is not about the quick launch but about the task bar. The only way to explain is with a link to what I see on my screen: