I'd like to make use of a VPN to provide security when using a PDA or laptop over unencrypted WiFi, or when using any Internet connection abroad.

I'm looking for something that will support the whole deal - Web browsing, streaming media, VoIP.

Encryption sufficiently strong to foil government security services preferred.

I don't have a dedicated computer at home (or a dedicated home, for that matter), so running my own VPN and connecting through that is not an option.