CISCO:

• Cisco Network Service Architectures (ARCH)
• Cisco Certified Entry Networking Technician (CCENT)
• Cisco Certified Internetwork Professional (CCNP/CCIP)
• Cisco Certified Network Associate (CCNA)
• Cisco Certified Network Professional (CCNP)
• Cisco Certified Security Professional (CCSP)
• Cisco Voice over IP (CVOICE)

CIW:

• CIW
• CIW Security Professional
• CIW Site Designer
• CIW Master Administrator

CompTIA:

• A+
• Linux+
• Network+
• Project+
• RFID+
• Security+
• Server+

Microsoft:

• Microsoft Certified Systems Engineer MCSE
• Microsoft Certified Systems Administrator MCSA
• Microsoft Certified Application Developer MCAD
• Microsoft Certified Solution Developer MCSD
• Microsoft Certified Database Administrator MCDBA
• Microsoft Certified Desktop Support Technician MCDST
• Microsoft Office Specialist MOS
• Microsoft Application Specialist MCAS
• Microsoft Certified Technology Specialist MCTS
• Microsoft Certified Professional Developer MCPD
• Microsoft Certified IT Professional MCITP

Red Hat:

• Red Hat Certified Technician RHCT
• Red Hat Certified Engineer RHCE
• Red Hat Certified Security Specialist (RHCSS)
• Red Hat Certified Datacenter Specialist (RHCDS)
• Red Hat Certified Virtualization Administrator (RHCVA)
• Red Hat Certified Architect (RHCA)

Oracle:

• Oracle Certification

Sun Microsystems:

• Sun Certified Java Associate SCJA
• Sun Certified Java Programmer SCJP
• Sun Certified Java Developer SCJD
• Sun Certified Web Component Developer SCWCD
• Sun Certified Business Component Developer SCBCD
• Sun Certified Developer for Java Web Services SCDJWS
• Sun Certified Mobile Application Developer SCMAD
• Sun Certified Enterprise Architect SCEA

Ubuntu:

• Ubuntu Certified Professional UCP

More:

• Computer Certification Guides
• Computer Certification Guides (eBooks)