I dunno, I'm going to disagree with both posters.
A. Mid-season might not be the best time to gain weight. Whatever you do, don't forget that hockey is job #1 right now. I'm not saying gaining weight is wrong, just don't let it interfere with your game. You need to focus on speed and conditioning at this time as well as strength.
B. The 5x5 is a great program. dhockey should read it and know it by end of season. But it's too much to handle this time of the year.
I'd start with something like this:
Westside for Skinny Bastards A modified lifting program for "Hardgainers"
and then make some important changes to allow for in-season:
Go heavy on bench and DL only every other week. Otherwise, go 8-10 or choose alternate exercise.
Don't deadlft from the floor. set the safety bars in the rack at, just below or above knee level.
You want to concentrate on developing your posterior chain which means squats, deadlift, Romanian Deadlift, Glute-Ham Raises, your lats (to handle action along the boards) which means barbell/dumbell rows, and pull ups, and on getting a strong core.
Try to get as much as possible of your conditioning done on ice.
If, at any time, what you're doing starts to interfere wit your performance at the rink, cut back. Remember, more isn't necessarily better, but how you spend your time is. You need enough time to recuperate or you'll end up losing instead of gaining weight.
No working out on game days!
At 17, you're going to grow anyway. BBlazer is right when he says to eat as much of the right foods as you can. This is at least 50% of the answer to putting on weight and the only way to do it without slowing you down.
Go over to the diet forum and read up. You'll save yourself lots of time and frustration . Here's a quick summary of what you need to do:
John Berardi - 7 Rules