Wordpress Hack Redirect to auto-im

i just have this problem recently, it's make me so mad and so confuse. i dont know where is the code for the injection.. this happen when i upload some plugin to my WP then some my content when i click the link it's redirect to another link that i dont know where it come.
and then i FIXED this problem.

first
go to your WP files --> wp-content --> themes --> your themes --> open index.php and header.php

for index.php
in the bottom of the page you will found some awkward php script its contain <?php and end with ?> delete it

for header.php
between tag /head> and  and <body, that have some java script <script and end with /script> just delete it.

end problem fixed !