I can try to answer that for you, since Alan doesn't seem interested
From July 1st this year you'll need a visa. Before that date you need a passport and invitation or voucher. Get in touch with your local Polish consulate. Here are the details of the one in Moscow:
If that's where you're travelling from, the train's cheap and surprisingly comfortable. The trip takes the best part of a day, but you can sleep in your couchette for most of that, and won't be bothered until you get to the Polish-Belarussian border. I'd heard horror stories of travellers on this train being relieved of their possessions and money, but it at least felt safe.
--- --- --- --- --- --- --- --- ---
Replying to:
What do I need to travel to Warsaw, being a Russian citizen?