Post any helpful references that you find in this thread, for the benefit of others. Also include a short description. I will try to categorize things by subject (i.e. particle physics, gravity, etc.). Leave a link, and a short explanation of what is at the link, and I will put it in its appropriate place in this thread.

General Physics
Motion Mountain Free Physics Textbook
Free for download in pdf.

Classical Mechanics/Electrodynamics
Open Text
This is a project by a former professor of mine (Walter Wilcox) to make free textbooks available to grad students. Included are textbooks on quantum mechanics, classical mechanics, and electrodynamics. These are good references, I think, although you have to watch out for typos. I have solutions to all of the problems in the electrodynamics book, if anyone is ambitious.

General Relativity
Lecture Notes in General Relativity
A textbook by Sean Carroll.

Particle Physics
Particle Data Group
A complete listing of all known particles, and their measured properites. Also includes reviews on everything from statistics to grand unification.

Quantum Field Theory
Free pdf version of Mark Srednicki's QFT text book. I have used this book on occasion---it is easy to follow and is a good compliment to something like Peskin.

Weak Interactions in Particle Physics
Free textbook by Howard Georgi, about weak interactions. I've never studied from this book, but Georgi was one of the founders of the subject, so I feel confident that he knows what he is talking about.

Semi-Simple Lie Algebras and their Representations
Once you had to pay for this book, but it is a very good introduction to some of the necessary maths for particle physics. By Robert Cahn.

Cosmology.

WMAP. The marquee experiment for cosmology. WMAP measures temperature fluctuations when the photons first decouple from the plasma that is filling the early universe. This happens at t=380,000 years or so. WMAP has given us some truly remarkable information about the Big Bang and Inflation.

SciReources

This is something that never really caught on, despite my best hopes Either way, here is a link to the thread (which has been unstuck) if anyone is interested in interesting physics, as explained by SciForums members:

http://www.sciforums.com/showthread.php?t=74474

I definitely think that the Motion Mountain textbook deserves a mention. Free for download. Pdf format. It's a basic physics textbook.
http://www.motionmountain.net/index.html

Thanks Ben!!! I be following up on this!!!

I found a link to some free-to-air (Japanese) papers courtesy of Progress in Theoretical Physics (The Japanese).

These are the heavies: among the most cited in the last 5 decades ..

A snapshot of how QT developed since the 1950's. Thought I'd leave a pointer to this here:http://www.ipap.jp/highlights/ptp.html

Hmmm... Is it a coincidence that all of these are papers by Japanese scientists?

None at all, it's the Japanese institution.

You gotta' get yourself one of them Concise Science dictionaries. Great fun.. Leads to sooo much...
http://www.wardsci.com/product.asp_Q...y,+4th+edition

If we could find a free online book akin to Arfken's Mathematical Methods for Physicists, that would be incredibly useful. I wonder if such a thing exists... maybe MIT has a course like that with online notes?

Bork---what kind of math textbook do you want? I'll see if I can find a math methods textbook.

Well I don't really need one for myself, I have access to a pretty big stash of resources. What I mean is if we could find a good public domain math methods book for people who want to learn physics, I think it would help alot. It could be used as a learning resource for people struggling to gain the background they need. Arfken's book, for instance, covers a massive array of difficult subjects such as Fourier transforms, boundary value problems, generating functions, etc. It's sprinkled with applications to problems in quantum physics, electromagnetism, nonlinear dynamics and many other areas of mathematical physics.

It would also be nice if an entry level math methods book were available to teach people here about complex numbers, geometry and other things they might be lacking. A kind of go-to reference guide when they need to learn a new concept.

Sometimes you encounter the odd good stuff online: this is a reference that covers quite a bit of ground, it looks at spiral forms in nature, in mathematics, in crystals; vortices and waves; and the anthropology (of numbers).
It's a google book with arbitrarily censored pages (about 2 or 3 every dozen or so) which means it's got missing bits, but what you can see looks quite good. It's an interesting treatment (I think) of the science of numbers, or mathematics and why we use it.

Beyond Measure: A Guided Tour Through Nature, Myth, and Number, by Jay Kappraff

P.S. has anyone heard of this Kappraff guy?

Thanks!! Just downloaded it. I'll check it out.

Thanks for the thread.

I find this site very interesting. Not only the great blogs, but the links and features too. I recommend it and suggest to readers that you explore around in it and see if your don't agree.

Very Cool Stuff, Thanks!!

http://e-research.lib.harvard.edu/V?func=quick-1

http://arxiv.org/

http://libweb5.princeton.edu/ejournals/by_title_zd.asp

Google books now has: "Quantum Computation and Quantum Information" - Nielsen & Chuang, Cambridge Press

Restricted, but still lots of 'free to air' pages. Anyone into computational complexity, algorithms, etc, should have heard of this one.

physics and math papers:
http://arxiv.org/

i see cheski beat me to it.

karl's calculus tutor.
http://www.karlscalculus.org/index.shtml

Ok this site has a download book of every type of math. I LOVE IT.
http://www.freebookcentre.net/Mathem...ons-Books.html

oops sorry I didn't go to the root of the site it's actually a site that has books to math, physics and computer science. ALL THREE OF MY INTERSTS YAY!!!!!!!!!!!!!!!

http://onlinebooks.library.upenn.edu/

An array of books...including the one I am presently working on

Axiomatic set theory
http://onlinebooks.library.upenn.edu...20set%20theory

It's difficult to navigate, but well worth the effort.