I thought this post on Trading Labs was informative for those thinking about going into this. http://www.trading-lab.com/forums/introduction_proprietary_trading-t305.html Please do your research carefully with any firm before joining. I saw the other day in a chat room some guys trying to recruit people for their "business" and things didn't add up.
Here's another good resource for those interested in this type of trading. PROPRIETARY TRADERS OVERVIEW by GreenTraderTax http://www.greencompany.com/PropTraders/Traders.shtml