廿分電腦問題 上網 (無線+有線)

you need a wireless broadband router (4-port+wireless) and a USB WIFI 'finger'.

Golden computer arcade has many brand/models for you to choose, namely, D-link, Linksys, Buffalo, LevelOne, Planex, etc.
高登自動報價系統 (無線網絡) 硬件價格http://www.hkgolden.com/hardware_price/wifinet.asp

Depending on your needs, but would recommend 802.11G type (54g) good enough for daily normal Internet surfing, email, online games....
1. $3xx to $5xx for wireless router
2. $1xx to $2xx for WIFI usb dongle (finger)

The above prices (router and usb) is based on 802.11G (54G) which is good enough for normal Internet surfing.

then use router cable attach to broadband modem.
then your existing PC with LAN cable attach to router.
then you need to install the USB WIFI dongle to your other PC (desktop/notebook).

This is the simplest way and short description on how to setup a wireless network.

Read these links for details :-
http://www.microsoft.com/athome/moredone/wirelesssetup.mspx (Microsoft)
http://www.microsoft.com/windowsxp/using/networking/setup/wireless.mspx (MS)
http://www.openplatform.com.hk/Knowledge/WRT54G_HKBN_b.htm (LinkSys)
http://www.resnet.uci.edu/routersetup.asp (LinkSys)

一般 Wireless Router 附有 4個LAN綫 port位,

即有線 & 無線可同時分享寬頻 !!

所以閣下的問題應該不用担心 ^_^