There is a plugin
WP-Cron which ignores post-dated articles when they are saved, but checks every 15 minutes if any have been published, and if so updates the pings and trackbacks.
But it is also worth reading
this article to understand how inefficient pinging is: of all the sites pingomatic (the WordPress default) pings, only two are likely to list your site). And BTW if inspired by the shortcomings of pingomatic and its competitors, you decide to put in 40-odd individual sites to ping, schedule lunch or something after you publish each article...