Yesterdaynight i finished the Sherlock-I, with the same equipment as i launched the HoHoHo-I. What i did: i have an iPhone with unlimited data. So i hooked my iPhone's simcard to my arduino, together with a GPS module. I figured out how to send data to webservers with this simcard. Hence the Sherlock-I server.
Summarized: an Arduino Mega with a -everywhere- free connection to the internet (my server) that loads up GPS data from where it is. Then everyone with an internet connection can LIVE track that via my Sherlock-I server. See schematic or See video on website: http://hollandshoogte.wordpress.com/
Video is here: http://hollandshoogte.wordpress.com/