If you are planning to upgrade from Oracle9i Release 2 to Oracle 10g Release 2, you must be at Oracle 18.104.22.168 or higher to go directly to 10gR2. This information can be found in the Oracle Database 10g Release 2 (10.2) Upgrade Guide.
If you do not want to first patch your 9i binaries to 22.214.171.124, you can investigate using export and import to upgrade your database to 10g. This choice would depend on how large your database is. If you have a fairly small database, using export and import may be a good choice.
There are many new features in Oracle 10g which you might want to read about in the Oracle Database 10g Release 2 (10.2) New Features Guide.
Even though you may not be able to utilize many of the new features in 10g, it is a good idea to remain at a supported database release. Having said that, it appears that Oracle 9.2 now has extended support until July 2010 and 10gR2 until July 2013. Click here for more information about Oracle's lifetime support policy.
This was first published in June 2006