This is vijay. I did my MBA in systems and now working as a Research Analyst. Its good to have work experience before doing MBA. Then it will be easy for you to cope up with the competitive environment.
Many of the B-schools provide campus placements. They prefer young, energetic individuals who can understand current business scenario. So, decision making is important before joining a B-school if u r a fresher.
If u want a job off-campus then its better to have 1-2 years of work-ex. Employees recruits both freshers as well as experienced graduates. But u should have experience in the fields like systems, Finance, mktg etc.