WireGoggles Free

Displays real-time wireframe outlines of what your camera sees. Choose from 16 color schemes or create your own. The free version cant save pictures; upgrade to the full version for that. Works best on fast devices like the Nexus One.

New in 1.7: Solid colors, Matrix color scheme. Please email if you encounter any errors.

Recent changes:
Support for front-facing cameras in Android 2.3 (Gingerbread). Use the Switch Camera button to switch between back and front cameras.