Thinking about what a newly hired developer should work through upon joining a company,

1. Company Products
2. Company Support Knowledge Base
3. Employed Project documentation (requirements, specification, source control)
4. Developer Processes (release notes, testing procedure, release procedure)
5. Professional Basics (see April 08, 2004 below)

(Some additional links)
5.1. http://ootips.org/ - great site
5.2. http://www.agiledata.org/ - some good essays
5.4. http://www.objectfaq.com/oofaq2/ - a bit dirty
5.5. http://javaalmanac.com - useful, wish it were maintained more regularly

The biggest company problem I've seen is when both management and developers have a knowledge gap on development and how to develop. Sad. Communication is a no brainer and it should be management that protects their investment in their staff. Hiring someone without any formally planned introduction with effective objectives and saying 'go code' is terrible.

Making sure that all developers are at the same level of communication is very important. Having one guru who doesnt see eye to eye with the rest of the team is a recipe for disaster. Is it up to management to ensure all developers have knowledge of the same concepts? Yes, but this also rests on the developers themselves. How can you call yourself a professional if you're not fully abrest of the concepts and correctness of your profession.