In the scene where Erin and her boss are talking in her house, it cuts to Erin and back to her boss, where if you look right above his head you can see part of a microphone stick-thing.
It gets me that you are so picky to see a very SMALL microphone but you don't know how to spell Erin's last name when she even spells it in the movie. B R O C K O V I C H
I recently found out something that may explain all the mikes and booms spotted in videos now. Apparently the movies are filmed in a wider format than is shown even on the big screen and the movie company is so used to the cinemas cropping the tops and sides to proper size that they aren't as careful as they used to be. This still makes it a mistake in my book, but it explains why they are as sloppy as they are. The site I read this on is www.straightdope.com Do a search to find whatever it is you want to know. A really interesting place.