last time i went from shanghai to suzhou i rented a taxi for the day. i'd like to take a train this time. has anyone done this? do i show up at the train station to buy a ticket or do i have a travel agent do it for me?

I wouldn't worry. There are trains originating from Shanghai heading west every few minutes during the day, literally. Unless you're going during major holidays, I don't think you need to buy in advance.

Thank's rkkwan. I speak a little Mandarin but no Cantonese. are tehre ticket counters with english speaking or ticket machines?

I don't know the set up at the Shanghai station, but if you speaks a little Mandarin, you should be more than fine. Just say "Suzhou", "Ruan Zuo" (for soft-seat), and show two fingers for two tickets, etc; and I think you'll be okay.

BTW, they speak Mandarin & Shanghaiese, not Cantonese, in Shanghai.

I have found the train service from Shanghai to Suzhou very good. I cannot remember how I got my ticket at the station - so it must have been pretty easy!! Make sure you get the better class seats and pre-book the seat - my carriage had tables and the trip was very comfortable. One tip - clarify times of return journey and allow time to get back to the station!!