I'm really getting excited about some of the location based web services we are seeing appearing. I really need a laptop with inbuilt GPS and wireless to make the most of them. Mmmm, gotta work on that one. For the time being Plazes is the service I'm finding most user friendly. Their software runs in the system tray. You have to set locations manually the first time but then it seems to recognize when you revisit the place. They have most of the features you'd expect from a good Web 2.0 service, except the ability to import your address book to look up which of your friends are already registered with the service. Below is a map showing where I last checked in.
My latest location tagged del.icio.us bookmarks are here and below.