hooke your router up. go to start run, type cmd for xp/xp pro/2000 click ok now type ipconfig. write down the default gateway ip then enter that into the address bar. click go.
98 user's start/ run/ type winipcfg click ok
using his address posted. click that..
ok look at the back of your router. should be a socket all by itself. should say phone line. now the other socket or sockets should say computer line. that would be where you plug computer into. if there are additional sockets those are for other computers. i will tell you this. do not go over 5 items after you have it all hooked up. like you can use a jack for 2 phone lines running off the one phone socket but do not split it again and have 2 comps running.