Google Latitude update every 1 hour
If you didn't try this already Latitude has a "Real-time updating" feature since Maps 4.6.  

To enable this: click on the person you want real-time updates from, on their Latitude profile you should see an option to get "Real-time updating".  Click that and you'll get another dialog asking how long you want the real-time update (15, 30, or 60 min).  When you go back to the map that that person will be orange instead of blue now.