If they want to, probably. Some of the ethnic groups in Afghanistan traditionaly wore some kind of veil anyway, but the papers have been carrying reports of women burning burqas. Hopefully, though, if they want to wear them they will be allowed to without fear of reprisal.
Maybe, though plenty of the forces who have been beating the Taliban are fairly extremist Muslims themselves. But chances are that clothing laws won't be quite so restrictive - particularly while they need the US's help to fight.