use LWP::Simple;
use XML::RSS;

while ( my $url = <DATA>) {
	chomp $url;
	my $xml = get( $url ) or next;
	my $rss = XML::RSS->new;
	eval { $rss->parse( $xml ) };
	next if $@;
	for my $item ( @{ $rss->{'items'} } ) {
		# do stuff with $item
	}
}

__DATA__
http://example.com/feed.rss
http://example2.com/feed.rdf
http://example3.com/feed.xml