I think all Windows XP Professional operating systems come with Chinese input. I don't know about Home Edition.
In Windows XP Professional:
In the Control Panel, go to "Regional and Language Options"
Select the "Languages" tab and make sure "Install files for East Asian languages" is checked.
The go to "Details," "Add...," whatever language you want, whatever keyboard layout you want.
The new year is celebrated differently in different places, but generally there's a lion dance somewhere, fireworks, lots of incense burning, money in red envelopes given to children, a big fat celebration, and probably other things I haven't mentioned.