Multiple monitor desktop software

Browsers
Browser 3D -
a unique multi-screen friendly browser that improves efficiency of Internet use and expands the view of activity, enabling users to simultaneously view where they are, where they have been and a preview of links and content. This is intended to facilitate Internet-based research.

Desktop for multiple monitor computing
Hydravision from Appian Graphics - a suite of multiple monitor applications designed to improve the efficiency of working with multiple monitor systems.

PowerStrip 3.0 provides advanced, multi-monitor, programmable hardware support to a wide range of graphics cards - from the venerable Matrox Millennium I to the latest Kyro II and GeForce3.

Silicon Realms Multi Desk - MultiDesk is a powerful and extremely fast virtual-desktop utility (and more!) which sits next to the Start button on your taskbar.

UltraMon
The essential multi-monitor utility for Windows:
Easily move windows between monitors
Manage multiple applications efficiently with Smart Taskbar
Maximize windows across all monitors
Create multi-monitor shortcuts
Disable all secondary monitors with one click
Run any screen saver in multi-monitor mode
Create custom multi-monitor desktop wallpapers
Mirror or zoom a window or monitor on another monitor
Preserve position of desktop icons

Screen Rotation utilities
Portrait Display labs (PDL) - Develops and markets software that virtually rotates video images from Landscape to Portrait.
Link to 9X Media. Sponser of the Multiple Monitors.org site

Link to 9X Media site Link to Multimon