Remove pound cake from pan. Slice lengthwise into three layers. I didn't have trouble slicing it frozen. If it's too hard for you, let it sit out just a few minutes and try again.
Place a piece of wax paper in the pan with about 4 inches excess on both long sides of the pan.
Return one layer of cake to the pan. Dot with dollops of sherbet and ice cream. Swirl.
Repeat with remaining two layers of pound cake, sherbet and ice cream.
Cover the top of the finished cake with wax paper. Freeze until firm.