I have 3 computers,2 of them are pc with win 98 oprating system and one is Mac (ibook)i have high speed internet connecting to one of my windows 98, i have a router too,how can i share the internet with my Mac,is there any configuration or software installation? thanks

Hook the Mac to the router and set TCP/IP to DHCP and you're all set.

p

I just went through this in setting up my own home network with one PC and two MACs, cable modem and wireless router. An ethernet cable connects the modem and router to my PC, and the router sends wireless signal to my imac and ibook (had to install airport cards on both).
I don't know if your router is wireless, but a word of caution to anyone using wi-fi...make sure you enable all available security features, including firewalls, encryption and mac address filters to prohibit unauthorized users from using your network. I also change my encryption keys on a regular basis.

If you have the internet going to your PC, you need to enable ICS (Internet Connection Sharing). Windows 98 didn't include that until Win98SE (Second Edition). You can get the upgrade/update for $15-20. Even then it can be a hassle since it isn't terribly obvious how to get things going properly.
If you don't want to give Microsoft more money, you can get free proxy server software to run on your PC and use the PC as a proxy server for your network.

Better option - if your modem (you didn't say if you have DSL or Cable) outputs to an ethernet RJ45 port - just connect that to your router. If it connects to a USB port, it may be easier/cheaper to connect it to mac to share your internet connection. Certainly the guys on this forum can help with the mac details.
Sharing the internet connection is easy. If you want the mac and PCs to see each other and share files, that takes more work.

The comment about wireless deserves a remark. Even if you set up WEP and the other standard "security", your neighbor or a guy sitting in a car outside can crack that in about two minutes. If you are doing stuff you don't want to share, like using a credit card to buy something, turn off the wireless hardware (so you don't broadcast) and use the machine hard-wired to the internet. Real wireless security is possible, but it takes some real hard work - probably not worth it in your situation unless you are a networking-security professional.

I have cable connection and 4 ports D-link router (not wireless)

do i still need ICS (Internet Connection Service)?

As long as you have a router, ICS is worthless.

p

thanks , it works