Oracle has some interesting 10G articles up on OTN:

• Auto-Tuning Oracle Database 10g Oracle Database 10g supports the automation of more routine DBA tasks than ever before. The techniques described here can help you begin to implement Oracle SGA self-tuning right away.
• Cost Control: Inside the Oracle Optimizer Designing new applications for the Oracle cost-based optimizer environment (or developing new ones)? Here's the latest information about how it works – as well as highlights of Oracle Database 10g enhancements
• Writing Better SQL Using Regular Expressions The regular expressions feature in Oracle Database 10g is a powerful tool for manipulating textual data
• Storage on Automatic The new Automatic Storage Management feature in Oracle Database 10g frees the DBA from a series of mundane tasks. This article describes its capabilities and applications.
• Setting a Date for Interoperability Calendaring standards are syncing up for collaboration.
• Taking Up Collections During its lifetime, Oracle PL/SQL has become faster, easier to use, and richer in its feature set. Oracle Database 10g continues this PL/SQL tradition of speed, ease, and feature growth by offering a useful array of enhancements.
• First Expressions Oracle Database 10g brings regular expressions to SQL.