My guess is that there are about 1500 speakers in total.

Interestingly, the best content for learning the language is in Spanish and Italian. Here it is in Spanish for example:

http://es.geocities.com/idohispania/k00.html
And the pdf:
http://es.geocities.com/publikaji/curso2.pdf

It's true that the English content is a bit lacking. One of my ideas has been to translate the Spanish course into English. It's copyright-free so there's no problem there.

I learned Ido through this site here:http://www.geocities.com/athens/sparta/6367/

As far as I'm concerned, the more people from your religion the better. I've known for a long time about the writing about a universal language, and have always thought that you would be able to provide a lot of help.