The Pinging app uses the management command manage.py blogping to generate the pings for the search engines. Set it up to run as a cron job.
You need to add the following statements to your settings file:
BLOG_TITLE = 'My great blog'
BLOG_BASE_URL = 'http://mysite.com/blog/'
Then register the extension. In yourapp.models.py:
Entry.register_extensions('blogping',)
Add pinging to your settings.INSTALLED_APPS.
Here is a list of servers that can be used for pinging: http://www.webpage-designer.net/65-wordpress-pinging-urls-you-need-to-know/