At Pudong Airport, you could take the coach to get to Hangzhou directly.

Thanks Jamie for the prompt reply.
I just found out that it is also possible to take an airport bus to Shanghai South Station and then from there take a train to Hangzhou.
I'll be arriving at Pudong Airport on 11 Mar 2010 2pm. So, which way will be easier and faster? Will it be crowded and difficult to buy a ticket? Thanks.

No difficult to get a ticket that day. If you can catch the shuttle bus, that is the easiest way, I think. It takes nearly 1.5 hours from Pudong airport to Shanghai South Railway Station and then another 1.5 hours on the train, plus the time spend on ticketing and transfer between bus and train. It will be not faster than taking the shuttle bus.