A quick and very simple question:

Is any material in these magazines available as Open Gaming Licences material?

That is to say, is any of the material in these magazines available for use in our own products?

If not, can they be converted to the Pathfinder Roleplaying Game and then used?

And finally, if none of the above is correct, say a magical item or character option interested me, can I simply create a new option in Pathfinder that uses the same rules?

How would I go about this?

Thank you in advance to those who help!

A quick and very simple question:

Is any material in these magazines available as Open Gaming Licences material?

No.

The safe answer is that none of it is open. None of it becomes open if you convert it to Pathfinder, or any other game system. When you use the Open Game License, you agree to "not to Use any Product Identity" without a separate license to do so. Product identity is defined as including (among other things) concepts and themes.
So by a strict reading of the OGL you agree not to use any concept or theme you find in any other product, unless it's been declared open content, without a specific license that says you can. Yes you could interpret this so broadly as to make it mean you can never use anything, since it's a concept used *somewhere*. People have, in fact, claimed the OGL actually says exactly that. Publishers have mostly ignored this interpretation.

As a writer and publisher I consider any concept so broad that I would feel safe writing a book I wanted to copyright and license without fear of being sued to be fair game for producing OGL mechanics. I never look at how any closed content rules handle an issue before writing my version of the idea, to avoid having my rules be derivative of theirs. By the same token, I would never feel comfortable trying to create an "open" version of content from Dragon, Dungeon, or any other non-OGL source.

I am not a lawyer. This is not legal advice. The Open Game License is a legal agreement, and if you want to publish under it, it's a good idea to get advice from a lawyer who understands how it works.

If you have ideas you want to write, give up looking at anyone else's old material and leap in with new ideas. We'd all love to see them!

Thanks very much Owen.

I think I'll take your last line of advice to heart and work from that.

And as someone who's just now begun to actually consider publishing, I figure I will definitely need to get more advice on the Open Gaming License.

There was Open Content Material, but not much. The d20 Dragon Annual had OGC, of course, as well as some older issues which I'd have to check. Although the Paizo staff should be more qualified to answer that question.

There was Open Content Material, but not much.

This may well be absolutely true. I have a vague memory of some open content, but to be honest didn't want to haul out my copies and thumb through them. I suspected the OP would have known if the specific material he wanted to use was open content, since it would have been marked, but I did choose to err on the side of caution in my reply.

There was Open Content Material, but not much. The d20 Dragon Annual had OGC, of course, as well as some older issues which I'd have to check. Although the Paizo staff should be more qualified to answer that question.

What d20 Dragon Annual is this?

I know of the DRAGON Compendium Volume 1 and the Dragon Annual 2009 (this last one is 4th Edition).

As for the DRAGON Compendium, the only OGC is the following:

The following text is considered Open Content: "Arcane Alterations: Templates for Spells." This Paizo Publishing game product contains no other Open Game Content. To learn more about the Open Gaming License and the d20 System License, please visit wizards.com/d20.

It's the 2001 Annual (also labeled as the "Dragon D20 Special" or something similar).

It's got little blurbs in some of the articles, an "OGC Tracker" that states either "This article contains no open game content" or it lists that which is open game content.

Released between Dragon 290 and 291, I think.

In fact, here it is.