Most computer retailers offers the Linksys WRT54G Wireless Router for about $49 and Wireless Access Points for $99. Why waste $50 if you don't have to? You can convert a wireless router to become a simple access point if that's all you need.
Step 1
Start with a wired PC. Document your current network's IP address scheme. In this example, the existing router was 192.168.0.1, and the DHCP address range is 192.168.0.101 ~ 200. Subnet mask does not matter for this example. Substitute your network addresses in place of these settings if yours is different.
Step 2
On the back of the router, remove the "Run CD First" tape. Do not connect any cable to the "WAN" port.... Ever. Put a new piece of tape over the "WAN" port socket to prevent you from trying.
Step 3
Disconnect the existing network cable from the back of your PC, set it aside for now. Take a new cable and plug into LAN port #2 on the new Linksys router and the other end into your PC.
Step 4
Reboot your PC to make sure it gets a new address from the new router.
Step 5
After reboot, start your browser and type in: http://192.168.1.1 - you will be asked for: Login ID = admin , and a Password = admin (Linksys defaults)
Step 6
Go to the Wireless Configuration page and start configuring the wireless options, such as Wireless SSID - Do not use "linksys", pick something else, like "charlie". 
Step 7
In the Wireless security settings page, use "WPA-Personal" level security at minimum, and a wireless security key at least 8 digits/letters long and you are done. Save the settings. 
Step 8
Go back to the main Router page, set the local IP address to an unused address on your current network. I set mine to the highest number in my network: 192.168.0.254. This puts the access point "out of the way", so to speak. Note: Some network routers are set by default to "start" in the high range (xxx.xxx.xxx.254), so if your network is like this, set the new wireless device to a lower unused number. 192.168.0.253 will do. 
Step 9
Set the "DHCP" Server to "Disable", again you will not need it, your existing router will give out DHCP addresses.
Step 10
Save the settings, the router will restart.
Step 11
Connect the cable from your existing network (disconnected in Step 3) into the LAN Port #1, and reboot your PC.
Step 12
Go find your wireless laptop, and log into your new wireless access point, satisfied that 15 minutes saved you $50.
Tips
- Do not use the IP addresses in this example unless your network is exactly the same.
- If you mess up, put everything back like it was, and reset the Linksys Router. Start from step 1 again.
Warnings
- Take note of the Wireless Security settings (Step 6). Do not leave your signal unprotected, it is an invitation for hackers and freeloaders to steal your network bandwidth, or worse.
Things You'll Need
- A Linksys WRT54G Wireless Router
- A new Ethernet cable
- About 15 minutes
