Wiretapping means connecting a concealed listening or recording device connected to a communications circuit. Most states nationwide have their own wiretapping/electronic surveillance statutes, which vary by state.
It is not illegal to record conversations if parties’ awareness and consent to the interception of the communication exists. There are certain limited exceptions to the general prohibition against electronic surveillance. The exceptions exist for so-called "providers of wire or electronic communication service" (e.g., telephone companies and the like) and law enforcement in the furtherance of criminal investigative activities.
A person can violate such statutes by the following:
Evidence of communications obtained in violation of these statutes may be suppressed at proceedings and persons illegally obtaining them are subject to lawsuit and/or removal from their position.
Generally, it is legal to record any conversation where all the parties to it consent (some state laws only require one person's consent). Federal law only requires one-party consent to the recording of a telephone conversation, but explicitly does not protect the taping if it is done for a criminal or tortuous purpose. Many states have similar exceptions.