Hi Ann,
yes, I have, many times. I lived not far from there for a year (I was just outside Krakow, in the south of Poland, and my best mate was living in Kutna Hora, just outside Prague).
It's a wonderful, amazing, enchanting city.
The cultural life is amazing - you will enjoy the concert!
It could be really cold - it can get as low as minus 20 in Feb, but could be 0 - 5 degrees as well.
I'm jealous, you will have a wonderful time!
Amy