How to contribute to ITIL
You have several easy options to choose from:
1. Be an author. Wait 3-5 years for the next ITIL Refresh. Tender for one of the books. Be one of about a dozen people worldwide to win a tender. Devote a year of your life to writing a book.
2. Know an author. Get networking now: you have 3-5 years to guess who the next ones will be and get into their professional circle. Then persuade them your idea is better than theirs.
3. Contact OGC to tell them you have some content to contribute. There is no documented process to do this, not any advertised contact point, but OGC are British government bureaucrats so you should find them helpful and communicative if you just send stuff off to any old address you can find. Once you have their attention, they will put you in touch with the next authors. See 2 above.
4. Forget it.
See the IT Skeptic's latest article for ITSMWatch for more detail on this open and helpful process..