OFX is an API standard used to send banking data directly to your personal finance manager (such as Quicken).
Is there any bank in Poland that offers OFX interface besides a typical web-2.0 HTML-based one?
Try Raiffeisen Bank.
I'm using Raiffeisen in Austria and the online banking system there lets me download statements in a variety of formats, including OFX. Perhaps they use the same or similar online banking in Poland?
I'm assuming you are asking to import your banking data into e.g. Quicken; not asking to upload data into the online bank.
Disclosure: I'm a Raiffeisen employee, but not in Poland. I have no financial gain from this.
Not QXF, but BPH has some SOAP API, but only for corporate customers: http://www.bph.pl/pl/klienci_korporacyjni/bankowosc_elektroniczna/bankconnect