Yes indeed! It's a Perl script called pflogsumm.pl written by James S. Seymour. The URL is:
http://jimsun.linxnet.com/postfix_contrib.html
You could then run this as a cronjob like so:
crontab -e 0 2 * * * /path/to/pflogsumm.pl -d today /var/log/maillog | mail -s "Mail Report" you@somewhere.com |