is phone sex considered statitory rape?

It's not considered statutory rape but it is against the law (section 288.2 of the California Penal Code).  It can be charged as a misdemeanor or for a second offense, a felony.  Basically, having telephone conversations or internet communications with a minor for the purposes of sexual arousal is punishable by incarceration - as a felony in state prison; as a misdemeanor in county jail.  

Here's the statute:

288.2.  (a) Every person who, with knowledge that a person is a minor, or who fails to exercise reasonable care in ascertaining the true age of a minor, knowingly distributes, sends, causes to be sent, exhibits, or offers to distribute or exhibit by any means, including, but not limited to, live or recorded telephone messages, any harmful matter, as defined in Section 313, to a minor with the
intent of arousing, appealing to, or gratifying the lust or passions or sexual desires of that person or of a minor, and with the intent or for the purpose of seducing a minor, is guilty of a public offense and shall be punished by imprisonment in the state prison or in a county jail.  A person convicted of a second and any subsequent conviction for a violation of this section is guilty of a felony.
   (b) Every person who, with knowledge that a person is a minor, knowingly distributes, sends, causes to be sent, exhibits, or offers to distribute or exhibit by electronic mail, the Internet, as defined in Section 17538 of the Business and Professions Code, or a commercial online service, any harmful matter, as defined in Section 313, to a minor with the intent of arousing, appealing to, or
gratifying the lust or passions or sexual desires of that person or of a minor, and with the intent, or for the purpose of seducing a minor, is guilty of a public offense and shall be punished by
imprisonment in the state prison or in a county jail.  A person convicted of a second and any subsequent conviction for a violation of this section is guilty of a felony.
   (c) It shall be a defense to any prosecution under this section that a parent or guardian committed the act charged in aid of legitimate sex education.
   (d) It shall be a defense in any prosecution under this section that the act charged was committed in aid of legitimate scientific or educational purposes...
  

Although the crime of rape usually requires some sort of penetration, just because penetration did not occur does not mean that an individual who engages in sexual conduct with a minor is not criminally liable for his or her actions.  In many states, this type of conduct could potentially constitute a "risk of injury to a minor" or "impairing the morals of a minor" type of crime, which are often felonies.  Moreover, since these are often strict liability crimes, not knowing that the "victim" is underage is usually not a viable defense.  If someone you know has been accused of engaging in inappropriate behavior with an underage girl, I strongly recommend consulting and/or retaining a criminal defense attorney in order to protect his rights and liberty.