If you would like more information about specific ESRI products (ArcPad, ArcIMS, ArcView, etc) check out the ESRI Software Products.
ArcScripts
http://arcscripts.esri.com/ Are you trying to do a process that doesn't seem to be supported in ArcGIS? If so go to ArcScripts to download plug-ins (created by other ArcGIS users) to install these very handy tools.
ESRI Support Center
http://support.esri.com/ Type in your question or problem in the search box, and a list of related items are returned in several different categories: Knowledge Base, Forums, and Downloads. This is a great resource if you are really stumped on a GIS issue.
ESRI Software Products
ArcGIS This software is an integrated collection of GIS software products for building a complete GIS for your organization. Learn more about ArcGIS products
ArcInfo This is the solution for delivering dynamic maps and GIS data and services via the Web. Help for ArcInfo
ArcEditor This is the complete GIS desktop system for editing and managing geographic data. Help for ArcEditor
ArcView (ArcMap & ArcCatalog) This is full-featured GIS software for visualizing, managing, creating, and analyzing geographic data. Help for ArcGIS
ArcReader This is a free, easy-to-use mapping application that allows users to view, explore, and print maps and globes. Help for ArcReader
ArcGIS Extensions (StreetMap, 3D Analyst, Spatial Analyst, Network Analyst) Help for ArcGIS Extensions
ArcView 3.x This allows you to easily create maps, and add your own data to them. Help for ArcView 3.x
ArcIMS This is the solution for delivering dynamic maps and GIS data and services via the Web. Help for ArcIMS
ArcExplorer This is the new, free 3D GIS data viewer available from ESRI. Help for ArcExplorer
ArcPad This is software for mobile GIS and field mapping applications using handheld and mobile devices. Help for ArcPad