Planner 5D is a free online floor planning and home design applications which comes with a lot of models and a 3D preview of floor plans. Free to use.

ExhibitCore Floor Planner is a free online floor plan software that allows you to create floor plans online. Try ExhibitCore Floor Planner Free

Placepad is a free online sketch pad to create floor plan online. You can sketch your floor plan to design your space and also make them available online for others to use as well.