No prosze, jak ladnie.
Poprawki:
Dear Tom,
Thank you for your letter from 20th March 2007. I would like to invite you for two weeks to Poland. There are many interesting places worth seeing HERE. We would (moze lepiej: COULD) go to Kraków. It's (A) very beautiful city with (THE) famous Wawel castle, (THE) Old Market(,) Sukiennice and Mariacki church. From Kraków we could go to Zakopane (-) "the capital" of (THE) polish (w angielskim duza litera: Polish) mountains if you like wandering (MOUNTAIN CLIMBING/ MOUNTAIN WALKS). There are punty (PLENTY OF) touristic (TOURIST)attractions there. You can taste (THE) special kind (OF Polish) cheese: oscypek. You should take some sport cloth (CLOTHES) (WITH YOU). Don't forget a warm pullover, cape (A HAT?) and comfortable shoes because in the mountains the weather is very changable (CHANGEABLE), sometimes it's very hot and sometimes suddenly very cold and windy.
Poland is a beautiful country.
I'm looking forward to your response.
See you soon.
Best wishes....