Nothing built in, but with all our programs you can just pass the query string as an option and the program will run normally. A cron job that ran:

/path/to/admin.cgi 'do=page;page=posts_delete_old.html;delete_old_posts=1;num_days=10;confirm=1'

would remove all posts greater then 10 days old. This is untested, but should work, so try it out on a test installation first. =)

Cheers,

Alex
--
Gossamer Threads Inc.