I spent the last week working with the Map Point Web Services from Microsoft. This application truly rocks. Almost everything I wanted to do, I quickly found in the SDK samples and docs.
One of the cool things about the service, is that you can upload your own “Customer Data Source” containing your points of interest, which the service will automatically geocode for you based on street address, and this data is then available to you when using the service. As an example, here's a map that shows all of the trucker sites near one of our terminals. The trucker data was data that we have here, that I uploaded to the Map Point server:

This data has to be in a specific file format, in order for the Map Point servers to correctly geocode it. Now, I had a bit of trouble getting started, mainly because I couldn't find an example of a Customer Data Source. Yes, there is an SDK document here that describes the format that your data file has to be in, but I'm lazy, and I just wanted an example!
So, I thought I'd provide one here. The format is simple, and you can add you own custom fields to be returned to your application, for example, I uploaded a “CompanyType” field that my application uses. Download my Customer Data Source file here.
The only thing I couldn't figure out how to do is upload an overlay, to outline our port. I'm not even sure that the Map Point service supports this. Overall, working with this has gotten me even more psyched than I already am about Web services in general. What a great application.
-Brendan