Here is how to submit a proposal to the XMPP Standards Foundation for consideration as an XMPP Extension Protocol:
Contact the XMPP Extensions Editor so that he knows to expect your submission.
Write your proposal following the guidelines described in XEP-0143: Guidelines for Authors of XMPP Extension Protocols.
Make sure you read, understand, and agree to the XSF's IPR Policy before you submit your proposal!
Email the XML file (or a URL for the file) to the XMPP Extensions Editor with a subject line of 'ProtoXEP: [your title here]'.
Note: It is the author's responsibility to provide a properly-formatted source file (see the template file maintained under source control). Proposals submitted in HTML, TXT, MS Word, Open Document Format, etc. will be returned to the proposal author for proper formatting.