If you have ski poles or hiking poles with snow baskets, along with crampons, then you will travel up and down pretty well.

The ice axe is for your safety -- If you slip or trip, (and know how to self-arrest) it can save your life. Do NOT glissade (sit down and slide down feet-first) without an ice axe to use as a brake. If you get into an icy spot, you can take off like a rocket without a brake.

You can rent an ice axe at Elevation in Lone Pine: http://sierraelevation.com/

Go here:
http://www.whitneyzone.com/wz/ubbthreads.php/topics/18197/Links_to_important_Whitney_inf#Post18197
and check the links and videos on ice axe use.