I am concerned that the Oracle Web site does not offer notes or a checklist for those migrating a DB from 9 to 10g. What resources are available if I run into problems migrating a DB from Oracle 22.214.171.124 on Linux to Oracle 10g on Linux without going to Metalink? I would also appreciate a list of "gotchas" in this regard.
Oracle does have a document called the Migration Guide. It contains a complete, step-by-step guide to migrating from one version to another. If you do not have a copy of this document, then you can obtain it on Technet, but the docs are also on your Oracle 10g installation media.
If you run into problems, then your best resource is Metalink, but that requires a support contract. If you do not have that support contract, then you can post questions to SearchOracle.com and one of our experts can help you. You can also post to the various Oracle-related Usenet newsgroups.
For me, I haven't seen any gotchas yet. The upgrade is pretty straightforward. I would highly recommend recalculating statistics after your upgrade though!