You can share your Android phone’s data connection with up to eight devices at once, by turning your phone into a portable Wi-Fi hotspot. (for Android 2.2 or higher)
To enable Wi-Fi hotspot:
1 - Press Home , press Menu , and touch Settings to open the Settings application.
2 - Touch Wireless & networks > Tethering & portable hotspot.
3 - Check Portable Wi-Fi hotspot.
The phone will broadcast its Wi-Fi network name (SSID), it can be connected with up to 8 computers or other devices. An ongoing notification is added to the Status bar and Notifications panel.
To disable Wi-Fi hotspot:
4 Uncheck Portable Wi-Fi hotspot to stop sharing your data connection via Wi-Fi.