Roomtodo - Simple yet powerful online tool for interior design and floorplans with built in walkthrough module.
Floorplanner - Floor plan interior design software. Design your house, home, room, apartment, kitchen, bathroom, bedroom, office or classroom online for free or sell real estate better with interactive 2D and 3D floorplans.
Sweet Home 3D - Sweet Home 3D is a free interior design application that helps to draw the plan of house, arrange furniture on it and visit the results in 3D.
Palette CAD - Palette CAD is one of the easiest 3D design software for those people who want to use a simple to use program for interior designs.
SketchUp - 3D for Everyone
InnoPlanner - InnoPlanner is a commercial based interior designing software.