You get an error, Unable to Join Network Failure (error -3) when you try to connect to a Wi-Fi network.
1. Ensure that the Security setting for your iPod Touch matches the setting on the wireless router you’re connecting to. (WEP password, WEP hex or ASCII, WPA, or WPA2)
2. The wireless router may not always broadcast the SSID. In this case, you must learn what the SSID is, and enter it manually under Settings > Wi-Fi > Other . By default, many Linksys routers have a SSID of linksys.
3. Other security settings on the router can lock you out such as MAC address filtering. Research whether or not there are these types of restrictions on the wireless router.
4. If all else fails, you may need to reset your network settings on the iPod Touch. Clearing things out and starting over sometimes can work wonders. Open Settings > General > Reset and select Reset Network Settings.