Automatically connect to Wi-Fi nodes, but route everything through encryption
Lifehacker suggests an app called SSH Tunnel:


  SSH Tunnel is an app that allows an
  Android phone to connect to the
  internet using an ssh tunnel for a
  completely secure connection. It's
  great for those times when you've got
  no data signal, stuck at work or a
  coffee shop that only has public Wi-Fi
  available, and you need to be sure
  that nobody is snooping your sensitive
  personal information as you connect to
  sites.