Using Your Laptop As A Wireless Router
So for some reason you want to use your laptop as a wireless router.
This can be done using the Windows Internet Connection Sharing feature. This guide will cover how to set it up for Windows XP. For more information see:
http://support.microsoft.com/kb/306126
http://en.wikipedia.org/wiki/Internet_Connection_Sharing
If you review the above links you will see they don't mention how to use ICS to turn your laptop into a Wireless Access Point. So here how you do it.
You cannot use ICS if the network you are sharing has a IP range of 192.168.0.*
Step 1 - Create Your Wireless Network
Create your Ad Hoc wireless network
I personally like WPA because I find WEP keys very hard to remember.
In order to make this connection always available, ensure the following setting.
Step 2 - The Big Secret
In order for ICS to work with your wireless NIC you must set your wireless NIC with the following static settings:
Thank you so much to this post!
http://shepherdnick.wordpress.com/setting-up-a-pc-as-a-wireless-router-using-ics/
You will need to change this back to use any other wireless network with your laptop.
Step 3 - Enable ICS
On your physical network (the connection you want to share) enable ICS
Step 4 - Start Using Your Network
Join your wireless network the way you would join any other wireless network.
Unanswered Questions
I'm not sure if it is possible to not broadcast the SSID of your network. I was unable to locate any information on this. If anybody know please but it in the comments.
Conclusion
Hope you find this guide useful. You wouldn't believe how long it took me to figure this out.