Plural of Ho

NYT reports on radio host Don Imus's breast-beating over his inappropriate remarks about the Rutgers women's basketball team:

Mr. Imus last week described Rutgers University's women's basketball team as "nappy-headed ho's," and then days later said everyone needed to relax and should not be offended by "some idiot comment meant to be amusing."

 

First, Imus should be fired.  So says this blog.  This blog, which is an authoritative source on journalistic ethics.  Which represents the moral judgment of the community.  Which the powerful read and quake (if they're bad).  Which the oppressed read it and wonder if I'm calling them SHPOSes.

 

Second, should there be an apostrophe used when creating a plural of the word "ho"?  Is it "ho's" and not "hos"?

I need to know.