It is easy to hook up a wireless router with your cable modem. Most of the wireless routers will assign the IP addresses to your computer on connecting them to your PC automatically. The connection when using a wireless router should be something like this. Connect the modem to your wireless router and then you can connect your PC to this wireless router wirelessly.
If you have Windows XP installed in your computer then you can use the Wireless Network icon and check the wireless network available. Choose the wireless network that is applicable to you and click connect. This would connect you to the wireless network. You have to ensure that the protocol that you use in your PC matches that of the wireless router. Now open the internet explorer and use the IP address given for the wireless router and then you can configure it as needed. Check the instructions that came along with your wireless router to find out the password that is used to enter the configuration page.