How to Get Wifi without buying a Router

For Mac
for a wifi on mac you need the following things

Next, you will need to configure the Mac (connected to your modem) to share it’s internet capability to wireless devices. To do this, open your System Preferences and click on Sharing.

In the Sharing Pane, click on the Internet tab to bring up Internet Sharing. In this window, you want to select Share your connection from Built-in Ethernet in the drop down menu. Then, you want to select Airport from the “To computers using:” list.

Then click on the Airport Options… button to configure some wireless security options. You don’t want to be sharing your wireless connection with the whole neighborhood.Here, enter a WEP password which will be required from the laptop wishing to join your new wireless network.

I have found this to be an excellent solution for folks who don’t have a wireless router, but would like occasional wireless access in the home or small office.

FOR WINDOWS

Connectify : 

Connectify Hotspot is the most favorite choice among all others because of it's high up-time. It's simple to install and set-up and get's all your devices online in 5 minutes.

All you have to do is download Connectify from here. This software hotspot comes in two separate packages - Hotspot Lite and Hotspot Pro. Lite version can share only Ethernet and WiFi connections whereas Pro can share USB connections and fling files. Once you download and install Connectify Hotspot, you'll need to assign a SSID (Network Name) and Password and you're good to go.

DOWNLOAD LINK

http://www.connectify.me/

Search for the network from any other wireless device and try to connect. You got yourself a WiFi router! On Hotspot Pro console, you can check which devices are connected to your network. If you're sharing a WiFi network, put this computer at other end of your home, you just increased the range of your wireless! Start the Hotspot when you're done. 

hope u guys liked the post.....