I just set it up on my phone just to try it out. Does seem to be working but seems like the only way you can access it from your desktop is if you add it to igoogle which I don't use or like igoogle. Hopefully they just make a separate login for it. My question is though, when you exit google maps it asks you if you want to keep latitude going. I pressed yes but havne't had a chance to try it. I'm guessing it just runs in the background cause I haven't seen in in the main task manager in the corner. Also when you do a soft reset I am guessing you have to launch and then exit google maps again for it to stay working. Wonder if there is a way to start it without having to do that. I think it just came out today, so I don't know 2 much about it.
Here is the link if you haven't heard about it yet
http://www.google.com/latitude/intro.html