okay i don't know how much you know or how much help you want...
i wrote that just now and didn't test it, but it looks good to me. let me know if you need more help, or help opening all files in a directory or something.
# first you need to open the file:
#open file.xml for reading
#open titles.txt for writting, in append mode as to not wipe it each time this is run.
#now we want to read from it until we get an end of file, or a title tag
#ahh beautiful regex. i suggest running perldoc perlre so you can read more about it
# but basicly this says search for <Title> and capture everything in between (.*?)
# followed by a </Title>. and /i means ignore case
print TITLES "$1\n";
#break out of the loop, only one Title per file.