Actually yes, I should have said "By the D20 System Trademark License", however I'd just gotten up and was having a stupid moment. :-(
Thanks for correcting me Gallowglass!
For those interested, this is what the D20 STL says in the plainest terms:
1. The trademark for D20 and the logos is Wizard's.
2. They grant you the right to use the trademark stuff as long as you play by their rules.
3. If you use the d20 STL you agree not to contest ownership of the trademarks and wizards bits.
4. If you breach the STL you have 45 days to sort it out to wizard's satisfaction.
5. If you haven't sorrted it in 45 days they can consider your license terminated with no further notice.
6. If you are terminated you stop using or producing stuff bearing the d20 logo and using the d20 STL, plus you arrange for all distributers of your stuff to destroy what is left. You pay for it all.
7. If you don't do the above you can be dumped in a legal stewpot.
8. Wizards can change the STL Logos when they want and its up to you to change to comply. They don't have to notify you of changes. However, you don't have to change your already produced stuff.
9. Wizards can change the STL itself when they want and its up to you to change to comply within 90 days. They don't have to notify you of changes. However, you don't have to change your already produced stuff.
10. You can update your Confirmation Card (publisher details) any time you want.
11. Address for correspondence given.
12. Wizards have no obligation to provide you with support or maintinence for the STL.
13. Wizards isn't responsible for the content of products put out under this license, or what folks do with it.
Also along with this are the rules Hunter mentioned:
1. You may *not* change any set Defined Term (including stuff like Armour Class, Level, the alignments, etc), however you can add your own (like Defence, Prestige, etc).
2. You may *not* include a description of how to create a character, but may include options to be used in the same (such as feats, skills, etc).
3. You may *not* include a description of the process to follow when assigning or applying the effects of experience to a character, but may list the level-based abilites for classes and stuff.
4. You have to have at least 5% OGL content in any product.
5. You must clearly display that it is a d20 System Licenced Product and that it is covered by the license found at
www.wizards.com.
There are some other rules and guides, but this is the core of it (for more info look at the d20 section of
www.wizards.com).
I aplogise for boring those who wern't interested, but hopefully this should clear up some questions.
Take care,
Shane