Update: You can no longer download the old free Samaris Island of Adventure supplement, though you might find it floating around on the web. Instead you can buy the full color 300+ page Samaris book, which contains an immensely enhanced, fleshed out version of the city. Or, if you're not sure if it's your cup of tea, you can first try The World Beyond RPG sampler for a ridiculously low price. This booklet contains samples from Samaris too.
The new Samaris Game Companion
And a map from the old one
The old Dark Dungeon 2nd Ed. Samaris setting was used in our own gaming group for many years, and featured in hundreds of our adventures. The new Samaris is updated for The World Beyond (the commercially available update of Dark Dungeon), and is a full color book with special tools to engage your players (or your game master!), and make your city games easier and more fun. It also features a hundred contacts, a hundred location descriptions, hundreds of illustrations, dozens of creatures, items, adventure ideas, and so on.
And the old Samaris booklet