BackstageOL and Liongate is holding advance screenings for John Wick on Tuesday, October 21 in Houston, Tx and San Antonio, TX. You can enter to win a free pass to the screenings here.
It is not clear if these advance screenings will be open to the public so if you are in Houston or San Antonio and are interested in seeing the film early, you can call your local theaters and ask about it.
Update: Canadian readers, Mr. Will Wong has posted on his blog that eOne FIlms is holding advanced screenings in Toronto, Vancouver, Calgary, Edmonton, Winnipeg, Ottawa, Halifax and Victoria on October 22. He did not give a link and I am not seeing anything else right now. If you are in one of those areas and interested then call your local theaters and inquire.
Update X2: Many thanks to @DorkShelf for tweeting their link! For those in Canada, you can enter to win tickets to the advance screenings in Canadian cities listed in the update above here.