Dev.Hyperion.com (formerly www.essbase.com) is the definitive Essbase resource for the Information Technology/Developer community, where product information, online discussions, resource libraries, demos and downloads can be found.

OLAPUnderground.com is a site dedicated to the distribution of freeware Essbase information, applications, and code. This site offers free utilities that any Essbase developer may want to consider.

Mosha Pasumansky is a Microsoft employee who hosts her own Analysis Services web site with a variety of links to Microsoft OLAP technical articles and related books, code examples, utilities, additional web sites, and the Microsoft OLAP newsgroup.

SqlDTS.com is a Data Transformation Services resource web site that can provide help to users of Microsoft DTS at all levels of expertise. This site provides many DTS-based code examples, SQL Server news, knowledgebase articles, and troubleshooting tips.

SQL Server Performance.com is a performance tuning and optimization resource site for Microsoft SQL Server. This site provides in-depth articles, source code examples, suggested reference material, and job searches. This site also contains a section with tips for optimizing SQL Server Analysis Services (OLAP) performance.

SQLServerCentral.com is dedicated to many aspects of SQL Server (administration, TSQL, DTS, data warehousing, etc.) for users of all skill levels. They have a daily newsletter that generally has two articles regarding some aspect of SQL Server, a question of the day, some current questions/responses in their user group, and a script of the day.