Using Platial MapKit, I will show how to make a tabbed map collection for a website, using the maps I put together for Make: as an example.
You can go ahead and add Places to these maps. They will be going live on Makezine.com pretty soon.
So, try out the maps, get a feel for the functionality, and then proceed with this instructable to get an overview of what is needed to build something similar for your own site.
The Platial MapKit faq might also come in handy.
I am not affliated with Platial or Makezine more than being an avid user.
Step 1: Generate code for your maps on platial.com
Save that code in to a text document and label it for future reference.
Note: you can only publish MapKits of maps that you own. You can make the map first and add places to it, then get the MapKit code or you can create the map and get the code first, then add places to it. It doesn't matter which way you do it.