Hello my friends,
I have a little question. I have never used wireless network before, and now my dad decided to buy wireless thing so that I won't argue with my brother about internet use. We have 3 laptops and 2 desktops. Only one desktop is connected to internet. Now, what I want is that I could use it as router for my computer, I mean Enthernet, and I want to use Laptops for wireless.
When you tell me what kind I should get, could you please tell what kind of range it will work and how to set it up so that it will a security key, so my neighbors won't "use" my internet.

Lider

If you are buying new, go with 802.11G, make sure it is WiFi compatible as this may save you any future problems. I would go with a recognised make such as D-Link or 3com.
You will need a wireless router or Access point, on this simply turn on SSID and set a password, this will need to be entered into each laptop/PC using wireless before it can access the network.
Alternatively you can limit access to only the MAC addresses of your machines, preventing anyone else using it.

Wizard ICT. Microsoft Certified Professional

Most home WiFi routers also include a 4-port Ethernet switch so you can have your desktop connected directly to the router and your laptops connected via wireless.

Unless your laptops have built in wireless you'll need to buy wireless adapters for them. Preferably buy the same brand as your router; it makes it easier sometimes to connect.

To discourage hacking enable WPA encryption on your router and wireless adapters. It's fairly simple to set up and enable.

Listen, radio waves are inherently in-secure. That's the whole convenience of them, they friggin' go everywhere.
What you want to do when setting up a wireless network (and you're concerned about security) is limit the ways someone can connect to your LAN.
According to Cisco, there are 4 areas to focus on, they are:
1) Change the default SSID
2) Disable the broadcast of SSID
3) Enable WEP or WPA or equivelent crypto
4) Enable MAC Address Filtering
The details of the above four steps are beyond the scope of this post and are covered (usually step-by-step) in the Setup/Help features of the router itself.

"...I can see the color 'invisible'!"