Wireless networks are convenient, but you should use caution when connecting to unsecure public networks.  Private networks like MWireless and UM Wireless that require a password have security and encryption built in, so that hackers can't intercept the traffic between your computer and the network.  

Public networks, however, usually don't require any login and don't have any security measures, which means your network traffic could be intercepted and read by other people.  SNRE IT recommends that you avoid typing in passwords and other sensitive data (credit card info, banking data, etc.) while working on unsecured public networks.

If you have a wireless network at home, we also recommend that you configure it to increase security.  You should:

• Activate WPA or WPA2 protection (or WEP if WPA is not supported) and set a good WPA Key.  You can use this site to generate a secure key: http://www.yellowpipe.com/yis/tools/WPA_key/generator.php. Each computer connecting to the network will have to enter that key once to connect, and should then use it to connect automatically afterward.

• Change the default administrator username and password on your router.  Often router manufactures use "admin" and the username and admin (or nothing) as the password.  If you don't change this, anyone can connect to your router as an administrator and make changes to your network settings.

• Change your SSID (the name your router uses to identify itself to computers).  Most routers come with a default SSID containing the name of the manufacturer.  If you leave this as is, someone seeking to attack your router will know what router you have and can look up information about it, including user manuals and hacking guides, online.  Rename your SSID to something unique and obscure, not something that identifies the device, its location, or its owner.

More information about securing your wireless network can be found here:
http://www.pcworld.com/article/130330/how_to_secure_your_wireless_network.html
http://www.getisp.info/wireless-network.html