Netgore engine can be found at http://www.netgore.come
Saturn Valley Online can be found at http://www.skyon.be
A video tutorial for the Netgore editor (aimed at Earthbound map making but might be useful for everyone) about the following topics:
GrhDatas
AutoGrh Updater
Saturn Valley
New Map
ID
Map Properties
Graphics on map
Layers
Grid
Grh Cursor
Adding Grh
Snap to grid with shift
Shift drag to select multiple textures
Selected map objects
Tile Mode
Grh Data Editor
Bound walls
Entities on map
Wall entity
Teleport entity
NPC spawns