strange noise in a/c

hey the last week or so ive been noticing that when i drive a strange whistling noise comes out of the a/c. It gets louder and higher as i rev higher, does anyone know what this is, also for a while now sometimes white air comes through the a/c. Does anyone know what these to things could be caused by? thanks!\

:rant:

noone knows huh?

Have it checked for leaks.