Yes there is, it's named alarm. I'm not exactly sure what you mean by a remote shell... are you using Expect, or Net::Telnet or system('sh') or something else entirely? Nevertheless, your code is going to look something like this:

eval {
  local $SIG{ALRM} = sub { die "too long\n" };
  alarm 30; #seconds
  system( '/usr/local/bin/scp', 'me@example.com:foo.txt', '.' );
  alarm 0;
};
if ($@ eq "too long\n") {
  # time out
}
elsif ($@) {
  #something else went wrong
}
else {
  # ok
}
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Note that your remote command could involve a Win32 machine, however you cannot run this code on a Win32 machine as alarm is not implemented on that platform. Also not that you want your signal handler $SIG{ALRM} to be as simple as possible. The more it does, the more chance you run the risk of dumping core and other other unpleasant things