For the most part I agree with kainedamo.. but one of the reasons that burkas are a 'sign of oppression' is that they stand for the subserviant role that many Muslim women have held for thousands of years.
Thats interesting considering Islam has only been in existenced as an organized religion for over 1400 years.
Also burkas are only in a limited number of countries like Afghanistan (After the Taliban came into rule), and some in Pakistan, and northern India and is not indicative of the whole Muslim world.
IT IS NOT A REQUIREMENT OF ISLAM.
But, it doesn't make the banning of them right. If the woman wants to wear it and perpetuate the thought that it's okay to think of women as lower than men, then by all means perpetuate away. But when women are forced to wear them is where it becomes a true problem, and where a problem should be made out of it.