The title refers to "practice ice", a designated hour or so of time to practice and scrimmage the game. You can think of it like a pick-up game of basketball, except that usually you don't have to rent the court to play. For ice hockey, you do.
Finding opportunities to play the game starts simply by finding the ice rinks. So this is the first step for finding opportunities to play: find your local ice rink. Use the Internet, the Yellow Pages, and good old fashion social skills to locate the surrounding rinks in your area. I live in Greater Boston, and there are easily 10-15 ice rinks that I could skate at, and another 5-10 outside of 20-30 miles that I can drive to in order to get some practice ice. Your city or town may not have such options, but don't be discouraged. If you can find at least one rink, talk to their manager or supervisor, and he or she can point you to another one. Ice rinks are like golf driving ranges: they're usually in out of the way locations!
Nearly all ice rinks fill up their hours with public skating, figuring skating practice, then ice hockey, for the schools, and then (eventually) for the adults. If you're starting out, you should certainly begin practicing ice skating at public skating sessions. I did this for almost a year before I began to play ice hockey. Every day skating on the ice hones the one skill you need to get started in this game.
You should visit all the public skating sessions, to figure out which ones are less crowded. These quiet sessions let you experiment more on the ice. I've gone to early evening public skating, and early morning public skating, and they each have their merits. Once the public skating is finished, stick around and see who has the ice afterwards. Often it will be ice hockey. Introduce yourself to a player or an organizer, and see if there's room for another player. Usually there is! If the session is an "organized game", then find out more from someone in the group. Making connections like these is critical to expanding your network of players and ice.
(One thing that I never had to do was ask local schools for ice hockey advice. Depending on where you live, this may be a great opportunity to learn about other ice resources.)
Between driving to the rinks, and hanging out there, it should be clear that playing the game becomes quite the time commitment. This is even more so in the beginning of your hockey days, because you have to build up your local area knowledge. Stick with it! Eventually, your days fall into a rhythm of driving from rink to rink. I knew players that jumped from one stick and puck to another, and I would occasionally get invited to more ice. Stick with the game, and build your local knowledge.