Clients (your laptop for example) can connect via wifi or bluetooth and get access to the internet using the mobile connection (4G, 3G, 2G) or (in case you are using bluetooth) the wifi connection which is established by the handset.
Wifi-tethering creates a so called adhoc (peer-to-peer) network on most devices. Infrastructure-mode is suppported for some devices - including the HTC Evo for instance.
** FEATURES **
-) Access-control feature. Allow/deny clients to use your mobile-data connection.
-) Wifi-Encrytion. 128-bit WEP in general. WPA/WPA2 on supported devices.
-) Reduce wifi-transmit power (on supported devices)
-) Settings for wifi-ssid, wifi-channel, Ã¢??lan"-network and more.
This application requires a "rooted"-device and a (custom-) kernel which supports netfilter (iptables)!