Learning to ski powder is HARD, unless you do it a lot. I've been fortunate in that my last few Ski Weeks at Taos were visited by some deep powder, so I got bonus powder skiing instruction, which was invaluable. In my private ski wk 2 wks ago, we got dumped on with a total of 34"over several days, and I can say that with my instructor, Stephanie, I never skied powder so fast (and confidently) in my life!
As for skis, I've gotten to the point where I can use my Sheeva 9's (89 underfoot) in most powder, unless it's really deep (over 9-10"), or really fluffy. Then I break out my Atomic Backland 103's, although I'm starting to like them less, since they're considerably longer at 159 than my Sheeva 9's at 148, but that's off-topic.
All of this to say that if you can possibly swing it, it's well worth taking a powder day lesson or two. You'll learn all the different (proper) techniques needed to ski the powder, and will learn to love it instead of ruining your day being fearful (and perhaps getting injured).