there are indeed more and more foreign students here in Poland and more and more courses, including medicine, are offered in English.
The application process usually takes place via internet, but there it's not centralised (there is no website like UCAS), so you should take a look on the websites of the universities. Requirements vary, so make sure you check them!
I don't know anything about the recognition of the Polish diplomas, but since we are in the UE they should be recognised in Europe.
If you have more questions fire away or PM me. ;)