I’ve seen that a few blogs I have in Google Reader take around one hour to update. Updating your blog to your readers is called pinging. Of course, you can add as many services you like, but this list is working just fine. To add services you have to go to Settings > Writing and add the following list of sites in the Update Services area:
You can use Filip’s insane ping list, or:

• http://rpc.pingomatic.com/
• http://api.moreover.com/RPC2
• http://bblog.com/ping.php
• http://blogsearch.google.com/ping/RPC2
• http://ping.weblogalot.com/rpc.php
• http://ping.feedburner.com
• http://ping.syndic8.com/xmlrpc.php
• http://ping.bloggers.jp/rpc/
• http://rpc.pingomatic.com/
• http://rpc.weblogs.com/RPC2
• http://rpc.technorati.com/rpc/ping
• http://topicexchange.com/RPC2
• http://www.blogpeople.net/servlet/weblogUpdates
• http://xping.pubsub.com/ping

Pretty simple and effective. Found in the WordPress Codex. Bumps go to blogdan, Vlad and ‘mnealui .