Google Latitude is a new step in keeping your carefully selected friends aware of where you are, and I am busily exploring it. You run it on your phone and it tells Google where you are, so Google can tell other people you have authorized where you are. Works best on mobiles with GPS, of course, on my phone the reported location will always be a bit off since all I have is cell-tower triangulations.
However, this doesn't solve the main problem I have with friends and directions: forget always updating, I have always just describing "I am here" in a useful way at a single point in time. Now all these new phones are getting GPS and maps, so I should be able to send a location marker easily for their phones to display on a map. Just a two-click action to have my phone send a Geo-SMS (yes, we'd need a standard for that) of where I am right now to someone, who could then see on their phone's map application where I am and how to easily get ot it. Maybe even a standard to include in emails, a microformat like vCal and vCard with which dates and contacts are now easily included and exchanged.
Precise geographical location is something computers know, understand, and can communicate, yet somehow humans are the ones who end up having to negotiate them to meet up.