serpentine belt broke

What happens when the sepentine belt breaks? How often and how much to replace? Would the belt breaking be related to oil burning up? Any help would be appreciated.

Also noticed that power steering is not working, yet power steering fluid level is ok.

You should check it every 30k, and it seems most folks replace them around every 30-40k. Also, the belt drives the power steering pump. No belt = no power steering.

As for oil burning the belt is not related to it. Read this for more info:

http://www.geocities.com/endre_rl/isuzufaq.htm#faq4