First is the amazing website of the Grand Lodge of British Columbia and Yukon, and their longtime webmaster Trevor McKeown. The range of topics on the site can be seen HERE, and it explores well researched articles of biographies, customs, paraphernalia, anti-Masonry, symbolism, ritual, jurisprudence, and much, much more. If you are stuck for an answer to a general question about Freemasonry, this is a good place to start.
Brother McKeown is not that widely known outside of his jurisdiction, and his name doesn't often pop up when the best known living Masonic scholars are discussed. That's a crying shame, because he is dedicated and meticulous at what he does, and deserves the thanks of all of us.
Next up is Brother Ed King's Anti-Masonry Points of View website. His extensive site has been online since 1998 and is largely dedicated to the eternal struggle against anti-Masonry and bogus pseudo-masonic organizations. He is opinionated, occasionally sarcastic - and absolutely indefatigable at tracking down Masonry's detractors and frauds. On the side, he has also reviewed a wide variety of Masonic books, and they are available on the site, as well.
Ed has slowed down a little bit in recent years, along with being drafted into more work for the Grand Lodge of Maine, so updates have not been as regular lately. Nevertheless, his site is a great one for peering into a world most of us don't encounter on a daily basis, but flourishes largely unfettered online. Ed calls them like he sees them. It's a thankless crusade, and he handles it with a sense of humor.
Third up is Paul M. Bessel's Homepage. His Masonic topics START HERE. Like Ed, Brother Paul started his Masonic pages in 1998, and his site tends to be more historically and statistically oriented. He is a member of the Grand Lodge of the District of Columbia, and is the go to source of information featuring stats and graphs about Masonry in DC, the US, Europe, and Prince Hall jurisdictions, including recognition issues. He also explores historical topics, such as Founding fathers who were and were not Masons, and those involved in pivotal roles during and after the American Revolution. There is much, much more buried in the site. It suffers a bit from odd formatting, so you have to poke around to find hidden gems.
Unfortunately, Paul has curtailed most of his Masonic activities recently and has stopped updating the site. That's a shame for us all, but we should be grateful for the massive work he accomplished before losing interest. He does remain a member, so perhaps he will return in future. He has been a dedicated contributor to Masonic research, and deserves our deepest appreciation.
And no mention of online Masonic resources would be complete without pointing to David Lettelier's Phoenixmasonry Masonic Museum and Library. Over many years, he and his fellow contributors have amassed an enormous online collection of images of Masonic objects, collectables, and other ephemera, along with online texts of rare books and magazines like the famous The Builder, and many more. If you are hunting an image or description of an unidentifiable piece of Masonic collectanea, it's likely to be here.
There are certainly many other sites that are great repositories of great Masonic information, like the Masonic Renewal Committee, the Online Masonic Research Institute, the Knights of the North's Masonic Dictionary, the Pietre-Stones Review of Freemasonry, the Educator, the Masonic Awareness at the Speed of Light lecture series, Guy Chassagnard's The Old Charges collection, 3-5-7 Productions' Masonic Education Papers, Gary Dryfoos' A Page About Freemasonry (one of the first), the Phylaxis Society Prince Hall Masonic Research pages (especially their very detailed Commission on Bogus Masonic Practices section), and many, many more. Forgive me if I've left out your favorite, although many others are listed in the Links column over on the right side of this page, down a little ways.
These brethren all deserve our deepest appreciation for their work, so if you visit their sites - and especially if you use their information in papers, books, or websites - please acknowledge them as a source, and take a moment to drop them a quick e-mail and thank them for their labors.