Here are a few screenshots showing different parts of FreeCAD. They are not ordered in any particular timeline, so the images may differ from your actual version. See more screenshots submitted by FreeCAD users on the screenshot forum thread and on the "Show your project here!" Users Showcase forum part.
The 0.17 release
The 0.16 release
The 0.15 release
The 0.14 release
A jeep modeled by psicofil
A house made with the Arch module by rockn
Mesh curvature analysis by the Mesh module
Export to external applications with python macros
The 0.12 release
The 0.11 release
The 0.10 release
Measurement
The 0.9 release
STEP Data
With loaded Robot gripper
Robot gripper
On XP with Schenkel
Boolean operations on Shapes
Boolean operations
STEP
A screenshot showing FreeCAD importing and rendering a gCAD STEP model
IGES
FreeCAD on Windows Vista, with an IGES model from Rexroth loaded
Fancy
You can customize a lot of aspects of FreeCAD!
Boolean on Meshes
Mesh boolean operations in FreeCAD
Blender
Blender has an script to import FreeCAD files.
Drawing Extraction
Extracting a 3D part (STEP in this case) to a SVG Drawing Extraction View. This is fully parametric, if the part change the view follows.
FreeCAD vs. QCad
A screenshot showing how a same file gets rendered by FreeCAD and qCAD
FreeCAD vs. Inkscape
A screenshot showing how a same file gets rendered by FreeCAD and inkscape
Draft module
Freecad with the draft module loaded and a dxf drawing imported
Preferences
The preferences screen
On Ubuntu
The FreeCAD interface when you start it for the first time, on Ubuntu
Windows intaller
Windows installer at work
console mode
FreeCAD runs in console mode (without gui)
Save picture
Dialog to save a picture with arbitrary sizes.