For those of you who don't want to download the books on line for SQL Server 2005 but would like to see it online here is the link (http://msdn2.microsoft.com/en-us/library/ms130214(en-US,SQL.90).aspx)
Here are the links for the main categories
The Database Engine is the core service for storing, processing and securing data. The Database Engine provides controlled access and rapid transaction processing to meet the requirements of the most demanding data consuming applications within your enterprise. The Database Engine also provides rich support for sustaining high availability.
Analysis Services delivers online analytical processing (OLAP) and data mining functionality for business intelligence applications. Analysis Services supports OLAP by allowing you to design, create, and manage multidimensional structures that contain data aggregated from other data sources, such as relational databases. For data mining applications, Analysis Services enables you to design, create, and visualize data mining models. These mining models can be constructed from other data sources by using a wide variety of industry-standard data mining algorithms.
Integration Services is a platform for building high performance data integration solutions, including packages that provide extract, transform, and load (ETL) processing for data warehousing.
Replication is a set of technologies for copying and distributing data and database objects from one database to another, and then synchronizing between databases to maintain consistency. By using replication, you can distribute data to different locations and to remote or mobile users by means of local and wide area networks, dial-up connections, wireless connections, and the Internet.
Reporting Services delivers enterprise, Web-enabled reporting functionality so you can create reports that draw content from a variety of data sources, publish reports in various formats, and centrally manage security and subscriptions.
Notification Services is an environment for developing and deploying applications that generate and send notifications. You can use Notification Services to generate and send timely, personalized messages to thousands or millions of subscribers, and can deliver the messages to a variety of devices.
Service Broker helps developers build scalable, secure database applications. This new Database Engine technology provides a message-based communication platform that enables independent application components to perform as a functioning whole. Service Broker includes infrastructure for asynchronous programming that can be used for applications within a single database or a single instance, and also for distributed applications.
Full-Text Search contains the functionality you can use to issue full-text queries against plain character-based data in SQL Server tables. Full-text queries can include words and phrases, or multiple forms of a word or phrase.