A BS Degree In Information Technology or something similar.
CCNA (Cisco Certified Network Associate) is a good cert to have.
Microsoft Certified Systems Administrator (MCSA) or Microsoft Certified Systems Engineer (MCSE) could help but unfortunately these are going out the door and will be obsolete ending 2011. So its best to get one of the new Microsoft Certs like a Microsoft Certified Technology Specialist (MCTS).
Also most jobs will ask you to have like 3 to 5 years of experience in IT. So you may need to start with a lower Helpdesk Job while you study for your BS and work your way up.