The website is only in thai. Doesn't make sense to me, as most of their clients are foreigners. The little flag icons are unclickable.

Or is there an english version somewhere ??

http://chiangmaiimm.com/en/queue-online.html

There are separate websites/pages for Chiangmai Immigration and the online queue. In answer to Beng's question, nope, what you found is all there is (and, yea, given the number of foreigners who speak English, it makes no sense).

Cut and paste the url in to Google translate.

Translations a bit iffy but you will get the gist of it.