Yes. Black Friday is not a holiday.
no.
In the US, the day after Thanksgiving is not a federal holiday, so the mail will still be delivered.
YES
In Poland there is ;)
yes
Yes.
yes
Yes , the USPS delivers mail on Friday : 11/29/2013 .
Yes, it is not an official holiday.
Yes there is.
yes none tuesday-merry christmas
If by today, you mean Friday November 26, 2010, there should be mail delivery from the US post office. The day after Thanksgiving is not a national holiday in the USA. Many people have to work today, including the USA post office and mail carriers.