US citizen looking to relocate to Poland

The best place to ask about those things would be a Polish embassy in your country.
The only one I could help you is the renting time. Usually people ask for one year contract. Although here in Krakow, there are many apartments to be rented for a holiday period. Those tend to be expensive.

In your position, I would contact one of the estate agents (you can get then on the internet), they usually speak English and are very willing to help.

Good luck

Thanks, do you have any sites that you recommend?

lots of places available to rent long and short term, easy enough to do I know as I have,
it is cheap also compared to the UK and the USA, http://rentflatpoland.com/
lots more sites also like that one, just google rentals poland.
Lublin is a nice place to be, as is Krakow, Katowice etc
I would suggest sorting a visa out, coming over for a month with a view to booking places to stay via booking.com
I find them very cheap and informative regarding places to rent short term with ratings.
then you can try out a week in lets say katowice, then a week in warsaw, 1 week in Krakow, 1 week in Lublin
to get to each place take a mini bus, and it is very cheap once again to do this, the mini bus service is normaly in most bus ranks.
then you can look for somewhere for a year or however long your visa is after that :-)
any help you need simply pm me
cheers and enjoy