you don't need wireless router. However, with the router, it works better. if you don't use the router, you need to 1. setup AdHoc. 2. setup ICS for the intrenet access sharing. quoted from www.chicagotech.net.
How to use Ad Hoc connection
802.11b (WiFi) cards can communicate in two different modes, Ad Hoc- for direct card-to-card communication and Infrastructure - for communication through an Access Point. If your wireless network doesn't have an AP, you will need to set your cards to use "AdHoc" mode. When setup Ad Hoc mode, make sure all wireless clients use the same mode, channel, web keys and SSID. You may need to setup TCP/IP manually if you don't have DHCP.
How to use Ad Hoc connection
802.11b (WiFi) cards can communicate in two different modes, Ad Hoc- for direct card-to-card communication and Infrastructure - for communication through an Access Point. If your wireless network doesn't have an AP, you will need to set your cards to use "AdHoc" mode. When setup Ad Hoc mode, make sure all wireless clients use the same mode, channel, web keys and SSID. You may need to setup TCP/IP manually if you don't have DHCP.