Now that you have this project set up, you can do more...

Set up as a Wifi-to-Wifi Tor middlebox

We use Ethernet because it requires no configuration or passwords, just click the cable to get DHCP but if you want, its possible to set it up as a WiFi-to-WiFi proxy. You'll need two WiFi adapter, then edit /etc/networks/interfaces to add wlan1 and enter in the SSID/password for your Internet provider using our WiFi tutorial We don't have a tutorial for this project

Configure Tor to make your Exit Node in a particular country only

Its very easy to configure tor to give you a presence in any country of your choice. For example here's my torrc that makes me 'present' in Great Britain.
Replace aaa.bbb.ccc.ddd by the IP address of your RPi and GB by the country code of your choice.
Configure your browser to uses a Socks 5 proxy on aaa.bbb.ccc.ddd, port 9050

Log notice file /var/log/tor/notices.log
SocksListenAddress aaa.bbb.ccc.ddd
ExitNodes {GB}
StrictNodes 1

Set up as a Tor Relay or Exit Node

If you like using Tor, help make it faster by joining as a relay, or increasing the anonymity by becoming an exit node. Check out the Tor project website for how to edit your torrc to turn your Pi into either.