Crappies remain fairly deep until early April usually, so if ice out is earlier, look for them suspended in the 20 - 30 foot range. They will move into shallow coves adjacent to whatever cover they can find when the water hits the 50 degree mark.
As always, it's mostly a matter of finding them. Once found, most all year, they are usually fairly eager for the right presentation. In open water, small tubes or twisters, along with hair jigs tipped with small pieces of bait and fished under bobbers are the ticket. Small minnows also work when the water warms up a bit more, and often are the best thing to throw.
Tyler