Microsoft

MOS (Microsoft Office Specialist)

MCP (Microsoft Certified Professional)

MCDST (Microsoft Certified Desktop Support Technician)

MCSA on Windows Server 2003 (Microsoft Certified Systems Administrator)

MCSE on Windows Server 2003 (Microsoft Certified Systems Engineer)

MCDBA (Microsoft Certified Database Administrator)

MCAD.Net (Microsoft Certified Application Developer)

MCSD.Net (Microsoft Certified Solution Developer)

MCT (Microsoft Certified Trainer)

Comp TIA

A+ (Entry-level personal computer technology)

Network+ (Entry-level internet technology)

Security+ (Vendor-neutral baseline certification)

Cisco® certifications:

CCNA

CCNP

CCIE