So I love the idea of Fire Eagle and I use BrightKite a fair amount, but they both suffer from the same problem - currently, you have to update your location quite manually.
With the popularity of the iPhone, we're very close to a time where application on our devices can help us track our location. At that point, location "wallets" like Fire Eagle will become very handy. Social Networks will become more and more location-based, and local searching via Google will become common.
So on my Windows Mobile phone (HTC Mogul, which I really love) I decided to try out Loki and Navizon.
Both look like great services. Loki uses Google Maps and has a Windows Mobile version. It is very search-based, but I was unable to get it to use anything other than a Wi-Fi connection for location updates. That made it kind of pointless for me. I couldn't find the place to set my Fire Eagle account as the recipient of location data.
Navizon had a more involved installer for the desktop, but the application installed easy through ActiveSync. Their technology seems amazing in terms of the different ways they can perform geo-location, and they use a nice Yahoo Maps interface. However, it refused to detect the GPS in my phone, a-la Google Maps, and the Wi-Fi didn't appear to connect. Using the amazing phone-based location appeared to work, but it was really inaccurate - it had me many cities over.
So both services installed well and looked pretty good. In both cases, however, they were not usable for what I wanted to achieve. I guess I'll try again in a couple months, or wait until I can be bothered to grab an iPhone!