Internet Connection Sharing is a concept that has become very popular with people who run more than one machine at home, or in a small working environment.
It is not in fact only available for people running Windows 98/ME. With the correct software, one connection can be made available to any number of platforms simultaneously.
Essentially, what ICS does is allows client machines to access the Internet via a host machine that is connected using a traditional connect. eg.Modem Dial-up, cable, ADSL, etc.
This potentially allows a huge number of machines to use a single connection, but because they are all drawing from the one connection, the rate of access to each machine decreases with each new connection.
Sygate Home Network:
Sygate started with a program that was run on a machine on a network, and if there was no internet connection available for that network, it would allow you to dial-in and form one. But if there was a connection on a machine that had the program installed, you automatically had access via that machine.
Sygate have changed their program now, and instead of this simple peer-to-peer system, they now require that you have a server-client system, where one machine will always be dialling in, and one will always be drawing upon that connection. While this might be good for a business with a dedicated server, in a home environment when two computers may both have access to a phone line, and the role of being dialled in may be swapped, this system fails miserably.
Windows 98 ICS:
Windows 98 SE came with a small piece of software that is supposed to allows Internet connection sharing between multiple machines, providing that those machines all run Win98 SE and all use the MS IE web browser. However, It suffers from the same flaw as Sygate's newer versions, and that is that the configuration is static and unbending.
Windows' ICS also suffers from some rather dreadful installation problems ( some would say this could be expected from Microsoft ), and may need to be uninstalled ( with a reboot ) and re-installed ( with a reboot ) before it can be configured.
Wingate:
Despite also being a Server <-> Client system, Wingate is probably considered the premier internet connection sharing program on the market. This is mostly due to vast number of configuration options that the program brings, with the manager being able to control all aspects of the connection sharing, from which protocols are able to access, to what IP range can use the system and what services can be run.
What this means is that the manager can specify that only people on a certain section of the network can access the connection, and then they cannot perform any tasks requiring HTTP or Telnet operations, but have unrestricted FTP abilities.
This coupled with an extensive logging and auditing system makes for the most professional program on the market.
Availability:
A trial version of Wingate can be found at www.wingate.net
A trial version of Sygate Home Network can be found at www.Sygate.com
Windows ICS can be found with Windows 98 SE