I Love ORD
744 you saw in Krakow (Balice) was used to transport news reporters to Krakow during pres.Bush's visit there in May of this year, so it was a charter, although ELAL often flies their 744's into Krakow and Warsaw, for obvious reasons.
Second of all, as of now, there are no American air carriers in Central/Eastern Europe. DL
did serve Warsaw in mid 1990's, my mom flew with them once, LOT had a code share with Americans, as well as many other airlines in the region. United will start services to Poland in the time coming due to their new codeshare with PLL LOT, perhaps there will even be a service to Krakow, Warsaw is a sure bet.