You might be able to catch it on cable TV channels that show classic movies. Sometimes they air West Side Story. Another option is to rent or buy a digital copy from online stores like iTunes or Google Play.
One option is to check if your local theater is screening it. Sometimes they have special showings. Also, you could look for it on DVD or Blu-ray discs for purchase or rental at video stores or online.
One option is to go to your local cinema if it's still being screened. Another way is to purchase or rent it from digital stores such as iTunes or Google Play.