Never heard of them? OREGON is a large manufacturer of chain saw chain, bars, and sprockets. They provide their cutting chains to over 50 manufacturers in over 130 countries! Visit their site for sizing information and a wonderful FAQ on chain and bar adjustment, maintenance, sharpening and repair.
The North Dakota State University has a really great and to-the-point article on chainsaw safety. It was written by George Maher, Ag Safety Specialist. Written in 1992, it is still both up to date and comprehensive. If you want to read just one article on the subject, this may be it!
STIHL USA, at http://www.stihlusa.com, is a very popular manufacturer of chainsaws. They have full length safety manuals available at their site for download. These manuals include proper cutting techniques and also a maintenance chart to help you remember what needs to be done. Though the STIHL name (pronounded like the metal "steel")is ubiquitous in the manuals, these manuals are very generic and can be helpful to anyone.