There are many ways to create an online map, too many to even start counting. If you are looking for the ability to copy and paste a bunch of addresses into a webpage and somehow end up with a map, however, the pickings are a little slim. Most of the websites in the past that offered this service don't give you options to style your map, but MapBuild.net does now.
Here's an example map I made to show some of the features. Yes, I'm using those beautiful watercolor map tiles again :) Go ahead and click on a marker, it gives some information as well as a picture of the item. Enjoy and happy mapping!