Total Network Inventory: Professional PC audit and network inventory management software - fits best for a for companies of all sizes. Free for 60 days.
PortableApps.com - PortableApps.com is a website offering many free, commonly used Windows applications that have been...
Network Inventory Advisor - Network Inventory Advisor audits all network software and hardware simply and efficiently
Scoop - A command-line installer for Windows
Lansweeper - Lansweeper discovers Windows, Linux and Mac machines in your network.
Just Install - just-install - The stupid package installer for Windows.
Nmap - Nmap Free Security Scanner, Port Scanner, & Network Exploration Tool. Download open source software for Linux, Windows, UNIX, FreeBSD, etc.