Here you'll find a list of free online sites and such to use at your disposal. While this list isn't exhaustive of everything available and of everything I do utilize, they are the most visited and frequented by me. (For a list of articles I recommend reading, visit the "Good Reads" section.)
Also, this page will be updated from time-to-time with new finds I feel that should be included here for the sake of their importance and usefulness. If you feel like there's something I should add to this page or if there's a broken link, then by all means contact me.
Exercise video demonstrations by:
These Youtube pages are full of videos to see how to perform certain exercises. I should also mention that exercise names may differ between each page.
People Who Know A Lot & Other Good Stuff
Adam Rees: Adam's smart and very underrated. Aside from his blog posts, browse his videos on Youtube.
All Things Gym: Gregor posts A LOT of finds from all over the web. There's a ton of content related to various types of weightlifting.
Bob Takano/Takano Athletics: He's an experienced weightlifting coach who regularly discusses the various aspects of the sport from exercises to what's going on at the US or international level. The main site [second link] has many free resources for weightlifters.
Boris Bachmann: Boris knows how to deliver quality content and consistently gives food for thought. Be sure to check out his Youtube channel on squatting here.
Carmen Bott: If there was a female equivalent to Cressey and Robertson it would be Carmen.
Carter Schoffer: He has an extensive background in program design and nutrition and has been very helpful to me.
Charles Poliquin: Puts out more information than I can keep up with, but often short and concise pieces. He has a bit of a bodybuilding flavor to his work.
Dan John: Not mentioning Dan John is like not acknowledging a barbell is used in the bench press.
Dave Draper Iron Online: Great website full of articles and a friendly forum.
Eric Cressey: Physio-based approach; I'm a fan of his lower-body and shoulder articles.
Examine: Similar to Wikipedia, the site is a comprehensive database detailing supplements, health-related topics, and answers common fitness questions.
Gubernatrix: Aside from Carmen, the only other woman on this list. Sally [aka Gubes] has a diverse background in powerlifting, Olympic weightlifting, and strongwoman training.
James Krieger: Posts that are free cover nutrition hot topics, such as artificial sweeteners, the book "Good Calories, Bad Calories," and more.
Jamie Lewis: Breaks the monotony of reading similar material everyone else writes about with different training methods and topics. [Not safe for work or home]
Lift Hard: Kirksman brings a unique perspective on Olympic Weightlifting. He's been trained by coaches of various nations and knows the sport very well.
Matt Perryman: Offers the best free comprehensive E-book on strength training. Posts are excellent and very thorough.
Mike Robertson: Also physio-based approach compared to others; articles appear either powerlifting-influenced or on prehab/rehab.
Precision Nutrition [registration link]: Thoroughly answers many beginner questions on nutrition and provides further in-depth discussion on topics. Registration is required, but free to access the majority of content. You can view forum members' questions I've answered here.
The Sweat Pit: Site with comprehensive articles and very smart members. Great place to learn exercise-related information, powerlifting, Olympic weightlifting, Strongman training, and more.
The Tight Tan Slacks of Dezso Ban: Regularly posts articles from old time lifters. One of my favorite websites.
WL Shoes: A website dedicated to reviewing Olympic weightlifting shoes.
The above individuals and resources are some of the best and I'd say it's more than enough help for most people. While there are many links, browse and select a few to follow that interest you.
Additionally, feel free to check out my blog list for other sites that you may find helpful.