They dont use "fonts", they make custom fonts. However there should be a font similar to appear on the internet soon... else i'll make it the first post in my new blog
http://www.urbanfonts.com/fonts/rounded-fonts.htm not exactly same fonts but New Republic and Morderna looks very similar , there are other fonts too
Sorry this is about a year late, but I had to comment. The font they use is LaureHead find at http://simplythebest(dot)net/fonts/fonts/laurehead.html
Windows XP is 10 years old. People wonder why we are not installing Windows 7 on many netbooks. One reason: The power that netbooks have is comparable to the power we had 10 years ago, which is why most run Windows XP. As we continue to add more processing power, more hard drive space and more RAM, our operating systems and software add more graphics and consume more RAM and hard drive space.
I think they have made their a special font for using in their logo but you can search more. Maybe i am wrong.