Microsoft Windows
Traditionally, commercial tools for network management have typically been developed for Unix platforms rather than Windows. Those available under Windows tended not to scale well. In the last few years this has been changing rapidly, and many of the standard commercial tools are now available for Windows platforms. A number of packages support IP scanning under Windows. These include freeware, shareware, and commercial packages. Generally, these products are less sophisticated than similar Unix tools. For example, stealth scanning is usually lacking under Windows. (Personally, I'm not sure this is something to complain about.) Nonetheless, there are a number of very impressive noncommercial tools for Windows. In fact, considering the quality and functionality of some of these free packages, it is surprising that the commercial packages are so successful. But free software, particularly in network management, seems to have a way of becoming commercial software over time -- once it has matured and developed a following.
Cyberkit
One particularly impressive tool is Luc Neijens' cyberkit. The package works well, has a good help system, and implements a wide range of functions in one package. In addition to IP scanning, the program includes, among others, ping, traceroute, finger, whois, nslookup, and NTP synchronization. With cyberkit, you can scan a range of addresses within an address space or you can read a set of addresses from a file. Figure 6-3 shows an example of such a scan. 
Figure 6-3. IP scan with cyberkit
Here you can see how to specify a range of IP addresses. The button to the right of the Address Range field will assist you in specifying an address range or entering a filename. If you want to use a file, you need enter only the path and name of a text file containing a set of addresses, one address per line. Notice that you can use the same tab to resolve addresses or do port scans of each address. There are a number of other tools you might consider. getif, which makes heavy use of SNMP, is described in "Device Monitoring with SNMP". You might also want to look at Sam Spade. (Sam Spade is particularly helpful when dealing with spamming and other email related problems.)
Other Tools for Windows
The good news is that Tcl, Tk, scotty, and tkined are all available for Windows platforms. Tcl and Tk seem to be pretty stable ports. tkined is usually described as an early alpha port but seems to work fairly well. You'll want a three-button mouse. The interface is almost identical to the Unix version, and I have moved files between Windows and Unix platforms without problems. For example, you could create maps on one and move them to another for monitoring. Moreover, the tnm extensions have been used as the basis for additional tools available for Windows. If you use Microsoft Exchange Server, a topology diagramming tool called emap can be downloaded from Microsoft. It will read an Exchange directory and automatically generate a Visio diagram for your site topology. Of course, you'll need Visio to view the results. Finally, if you are using NetBIOS, you might want to look at the nbtstat utility. This command displays protocol statistics and current TCP connections using NetBIOS over TCP/IP (NBT). You can use this command to poll remote NetBIOS name tables among other things. The basic syntax is returned if you call the program with no options.