As well as the links listed in the sticky for this subforum, I figured some more resources might help people. Many of these sites have guides which should come in handy:
http://www.openbsd.org - The OpenBSD home page.
http://www.openbsd.org/faq/index.html - The official FAQ. Lots of helpful information here. Your first stop for information.
http://www.openbsd101.com/ - An excellent site for beginners.
http://marc.info - Mailing-list archive, which includes OpenBSD's mailing lists. Helpful to find topics that have already been discussed.
http://undeadly.org - OpenBSD journal
http://openports.se/ - Port tracking.
http://openbsdsupport.org/ - General documentation and guides.
http://www.bsdguides.org/guides/openbsd/ - Guides
http://www.nomoa.com/bsd/ - More guides!
http://www.weirdnet.nl/openbsd/ - Guides/tips.
http://opendoc.lindesign.se/ - More guides/scripts.
http://www.seifried.org/oag/ - Seifried's OpenBSD Administrator's Guide.
http://en.wikipedia.org/wiki/OpenBSD - Wikipedia coverage
http://vendorwatch.org - Information on the open-ness and contributions of hardware vendors to opensource developers.
http://openbsd-wiki.org - Unofficial wiki. Guides/tips.
http://bsd.phoenix.az.us/faq/openbsd - FAQs from the Phoenix BSD user group.
http://www.sanitarium.net/golug/OpenBSD.html - Great guide to installation and maintenance.
Feel free to add your resources.