The Collaborative International Dictionary of English v.0.48:

Squeak \Squeak\ (skw[=e]k), v. i. [imp. & p. p. Squeaked
   (skw[=e]kt); p. pr. & vb. n. Squeaking.] [Probably of
   imitative origin; cf. Sw. sqv[aum]ka to croak, Icel. skvakka
   to give a sound as of water shaken in a bottle.]
   1. To utter a sharp, shrill cry, usually of short duration;
      to cry with an acute tone, as an animal; or, to make a
      sharp, disagreeable noise, as a pipe or quill, a wagon
      wheel, a door; to creak.
      [1913 Webster]

            Who can endure to hear one of the rough old Romans
            squeaking through the mouth of an eunuch? --Addison.
      [1913 Webster]

            Zoilus calls the companions of Ulysses the
            "squeaking pigs" of Homer.            --Pope.
      [1913 Webster]

   2. To break silence or secrecy for fear of pain or
      punishment; to speak; to confess. [Colloq.]

   Syn: squeal.
        [1913 Webster]

              If he be obstinate, put a civil question to him
              upon the rack, and he squeaks, I warrant him.
                                                  --Dryden.
        [1913 Webster]

WordNet (r) 3.0 (2006):

squeaking
    adj 1: having or making a high-pitched sound such as that made
           by a mouse or a rusty hinge [syn: screaky, screechy,
           squeaking, squeaky, squealing]