perldoc -q timeout
Found in /usr/share/perl/5.8/pod/perlfaq8.pod
       How do I timeout a slow event?

       Use the alarm() function, probably in conjunction with a
       signal handler, as documented in "Signals"
       in perlipc and the section on ``Signals'' in the Camel.
       You may instead use the more flexible Sys::AlarmCall  module av
+ailable from CPAN.

       The alarm() function is not implemented on all versions of Wind
+ows.  
        Check the documentation for your specific version of Perl.
[download]

That should help.... check the specific docs for alarm and eval for more information.

Update:Actually, I just had a look and IO::Socket has its own timeout method. So you probably want to use that :p