Mikrotik Dude
http://www.mikrotik.com/thedude.php
The Dude network monitor is a new application by MikroTik which can dramatically improve the way you manage your network environment. It will automatically scan all devices within specified subnets, draw and layout a map of your networks, monitor services of your devices and alert you in case some service has problems.
RouterSim's CCNA™ Network Visualizer®
http://www.routersim.com/CCNA6_Home.html
RouterSim's CCNA™ Network Visualizer® 6.0 is a CCNA™ router and network simulator that offers more features and flexibility than any product on the market. You can design, build and configure your own network. With a program that offers 500 supported commands and over 190 labs, you are empowered to build, test and preview a large variety of networks! CCNA™ Network Visualizer® 6.0 is ideal for:
Anyone studying for the Cisco® CCNA™ 640-802 exam
Deployment over a LAN network
Distance education and deployment on a Citrix server or Microsoft Terminal Services
Corporate trainers and employees
Students at colleges, universities, and technical institutes