|The advent of the Open Gaming License has been a blessing. So much material is now freely available online to help the GM and Players work out the nuances of every rule. I have listed below a sampling of the System Reference Documents posted for each of the major D20 gaming systems I use. Unfortunately there are no legitimate online references for the Call of Cthulhu D20 system or the Star Wars d20 system.
In addition to these rules discussions I can heartily recommend a series of character generators by Ed Friedlander MD. He has created very easy to use generators for:
And here are some pretty decent Character Sheets, many from the Mad Irishman, who I am glad to see is still adding stuff to his site: