Quick links to useful resources and tools on Cisco.com :

General links :
Support Tools & Resources
Cisco Product Quick Reference Guide
Cisco NetPro Forum
Dynamic Configuration Tool
Pricing Tool
Cisco Community Central

Voice links:
Cisco IOS Voice Configuration Library
Voice Debug Lookup
Voice Glossary
DSP Calculator
Voice Codec Bandwidth Calculator
Cisco Power Calculator
Cisco Unified Communications System Release 7 Technical Readiness
CUCM Capacity Tool
Solution Expert
HP Server Solutions

Contact Centers links:
Partner Central IPCCE
IPC Resource Calculators
Call Center Forum 2008
Call Center Forum 2009