Passwordless Secure Wi-Fi

Well, actually I don't recommend that you disable security features like WAP2 and enable broadcast of your network ID (SSID), but there's a nice (complementary) way to keep all but your network devices out of your LAN which does not require any password nor fancy encription scheme, and that is to filter devices by MAC, that is only allow devices whose wireless MAC address have being previously entered in the MAC address filter list of your router.

For example, in my Linksys WRT54GL router's administration console, I go to Wireless > Wireless MAC Filter: click enlable; click Permit only; click on Edit MAC filter list; enter the MAC addresses of all my divices (palm, laptop, pc); click on Save Settings... wait untill the connection comes back... close that pop up window; and click on Save Settings in the Wireless MAC Filter page.