Upgrade 9i RAC to 10G RAC

Upgrade 9i RAC to 10G RAC:
A very nice and stepwise document to upgrade 9i RAC to 10G RAC database.
This article provides the procedures for converting Oracle 9i (9.2.0.4) RAC to Oracle 10g (10.2.0.1) RAC on Red Hat Enterprise Linux 3 (RHEL3).
http://www.arhun.com/techtalk/oracle9i-rac-oracle10g-rac.html

Upgrade Guide: Oracle9i Release 2 RAC to Oracle RAC 10g Release 2 on Linux:
If you've been waiting to take advantage of the extensive list of new features and functionality in Oracle Database 10g and Oracle Real Application Clusters (RAC) 10g, there's no longer any need for delay. In September 2005, Oracle Database 10g Release 2 and Oracle RAC 10g Release 2 became available on all major platforms.
In this guide, I will describe the various steps involved in upgrading an Oracle9i RAC Release 2 environment configured on Oracle Cluster File System (OCFS) to Oracle RAC 10g Release 2 configured on Oracle Automatic Storage Management (ASM)—which is best practice for shared storage on RAC systems. Part 1 will cover the basic upgrade process; Part 2 will cover OCFS-to-ASM migration.
Please note that this guide is intended for evaluation purposes only; it is not an amendment of, or replacement for, official Oracle documentation.

http://www.oracle.com/technology/pub/articles/vallath_rac_upgrade.html

Few other helpful links for RAC documents:
http://www.oracledba.org/index.html
http://download.oracle.com/docs/cd/B19306_01/server.102/b14238/toc.htm