I'll continue to add to this list as I discover useful sites, and welcome recommendations (though I cannot guarantee that I will include them). The same goes for link exchange requests: I won't exchange links just to make PhilosophyOnline more popular, so the link exchange request has to be meaningful for both of us.
Sister Sites - Other sites associated with Gareth Southwell or PhilosophyOnline
My Patreon Account - This is a crowdfunding site that I use to support all my activities - philosophy or art related. Pop over there and have a look, and support me if you can (pledges can be as little as £0.60/$1). All money helps keep this site and its materials FREE, and allows me to develop it further.
GarethSouthwell On Twitter - This is my Twitter account, where you can follow my daily 'tweets' (short, 140 character messages, for all you Twitter virgins). Nothing too profound, but I enjoy chatting, so feel free to drop by and say hello.
Google+ - Me. On Google+.
Art Related Sites - Portfolios, prints, mugs, t-shirts, postcards, calendars, and crowdfunding projects.
The Zazzle Shop - Here you can buy lots of philosophy related merchandise - t-shirts, mugs, calendars, etc. (well, eventually...). Buying stuff from here is also a good way of supporting the site and keeping resources free.
Art Website - You can see my illustration portfolio here.
DeviantArt Page - A wider range of art than my portfolio, including sketches, works in progress, competitions, etc.
Artflakes Shop - High quality art prints of my work, sold from Germany.
Society6 Shop - High quality art prints of my work, sold from the US.
General - Links to sites of general use to those interested in philosophy
The Internet Encyclopedia of Philosophy - A non-profit organisation, hosted at the University of Tennessee Martin. The articles are contributions from specialist philosophers, and are reviewed by the editors James Fieser and Bradley Dodden. The writing is generally accessible but scholarly and comprehensive. An extremely useful site.
The Catholic Enclyclopedia - This site is not officially associated with the Catholic Church, but is based on the Old Catholic Encyclopedia published in the US in 1914, and as such gives a good idea on the Church's stance on most things. Obviously, it's most useful for the amount of detail on religous matters, and for providing balance to the secular perspective on things.
The Stanford Encyclopedia Of Philosophy - Associated with Stanford University, the SEP contains contributions from current experts in their field, so content tends to be very reliable, detailed, and thorough. As such, it is therefore most useful for those already familiar with certain topics who are looking to go deeper.
Philosophical Answers - An extremely useful site run by the British Philosophical Association. It aims at helping teachers, especially those teaching ‘A’ level philosophy and ‘A’ level Religious Studies. Users can submit questions to a panel of university philosophers about how to approach the teaching of particular topics, how to interpret passages from set texts, or what reference works they might use to deepen their understanding of different areas of philosophy. There is also a resource bank, which contains a growing and regularly updated list of useful links and downloadable teaching resources.
Publications - Links to sites associated with philosophical publications
The Philosophers' Magazine - An international quarterly magazine set up by Julian Baggini and Jeremy Stangroom, and now edited by James Garvey of the Royal Institute of Philosophy, covering all aspects of philosophy for the academic, student and general reader. Very readable and interesting (their caricaturist is really good, too...).
Philosophy Now - An international monthly magazine edited by Rick Lewis, focusing on philosophical issues in a very engaging and readable way.
Think - A journal, edited by Stephen Law and published three times a year, which aims to forge a link between contemporary academic philosophy and the general public. Contributions are from eminent philosophers, but written to be accessible and interesting.
Philosophy - A quarterly journal associated with the Royal Institute of Philosophy, edited by Anthony O'Hear, and published by Cambridge University Press. Includes contributions from practising philosophers aimed at the 'serious non-specialist reader'.