Tools

Ethernet MAC Address Lookup / Fibre Channel WWN, WWPN, WWNN Lookup / Vendor Lookup
Gigabyte (GB) to Gibibyte (GiB) Converter - provides quick conversion between gibibyte (230 bytes), mebibyte (220 bytes), gigabyte (109 bytes), and megabyte (106 bytes).
Binary to Decimal to Hexadecimal Converter
IP Locator - finds the geographical location of an IP address or host.
WHOIS Lockup for IPs and many popular top-level domains.
EMail Tracer - analyzes email headers and presents basic information about an email massage in an easy to read table form.
IP Subnet Calculator
Password Generator - random password generator.

General

IEEE Registration Authority - Public Listings
Guidelines for Use of the 24-bit Organizationally Unique Identifiers (OUI) (IEEE)
The Unicode Character Code Charts
ISO lists of country names and code elements
IANA's Root Zone Database
TLD and CLTLD whois servers list

Network

Well Known Port Numbers (IANA)
Ether Types/Vendor Addresses/Multicast Addresses (IANA)
My IP Address Lookup and GeoTargeting Community Geotarget IP Project
Wireshark (formerly Ethereal), a software network traffic analyzer
robtex swiss army knife internet tool
IP Subnet Calculator
Subnet Mask Table

SAN / Storage

Guidelines for Fibre Channel Use of the Company_id (IEEE)
Stephen Foskett's Symmetrix World Wide Name Calculator
BackupCentral.com - Backup Central (W. Curtis Preston)
How Fast is a disk?
Getting the most performance from your HP StorageWorks Ultrium 960 tape drive white paper
The Storage Performance Council (SPC)
Clariion blogs

MS Exchange

Andy Grogan's "The Ramblings of an Exchange Admin" - telnetport25.wordpress.com
Slipstick Systems - Outlook & Exchange Solutions Center - www.slipstick.com

MS MOM / SMS / System Center

myITforum.com

MS Windows, Server Clustering

Windows Server Clustering & PCNews - The Blog by Rodney R. Fournier
Clustering and High Availability - Microsoft's Failover and Network Load Balancing Clustering Team Blog
Windows Sysinternals
EventID.net

MS SQL

St. Louis SQL Server User Group (STLSSUG) - User Group Presentations
SQLTeam.com
Grumpy Old DBA
W3Schools - SQL Tutorial

ORACLE

Configuring the Oracle Database with VERITAS Software and EMC Storage for Optimal Scalability, Mangeability, and Performance
Optimal Storage Configuration Made Easy (SAME)

Scripting

The Script Library. Free Scripts. Download Free Scripts. Submit Scripts Free.
Rob van der Woude's Scripting Pages - www.robvanderwoude.com
Microsoft / MSDN Library - Windows Scripting Resources
Microsoft / MSDN Library - VBScript Guide
Microsoft / MSDN Library - WMI Reference
Microsoft WMI scripting tool - Scriptomatic 2.0
W3Schools - VBScript Tutorial

VMWare

VMGuru.com
vmprofessional.com
vmMBA.com

Web

Full Web Building Tutorials - All Free - W3Schools.com
JavaScript Event KeyCode Test Page

Other Stuff

ThinkGeek.com
Despair, Inc.
Dilbert.com