To setup the OpenSSH port forwarding, we use the command

ssh -L8080:localhost:8080 outside.machine.net

Now your the port 8080 on your local machine will appear to be a proxy server which is really running outside the firewall.

Lastly, we need to set our browser up to use this proxy, so if you're using Firefox (and you should be) , then you go to Preferences, General, Connection Settings and choose Manual Proxy Configuration then fill in localhost and port 8080 in the HTTP Proxy field. Now you should be surfing through the proxy.

Now you're using this because either there are some web sites that are blocked by your firewall, or you are doing something nefarious and you don't want anyone to know, but the price you pay is that it's a little more sluggish than normal (with encryption and more connection requests, etc.), so you may want to switch back and forth between surfing through a proxy and no proxy. My suggestion for doing this is to make some script (bash with OpenSSH, or batch with Plink for Windows). You would just use the same command as above and maybe tie an icon on the desktop to it for easy access. Then anytime you want to surf through the proxy, just double-click the icon and then change your browser settings. Anytime you want to bypass the proxy, just change your browser settings. You could even have the port forwarding script run when you login, but I'd usually suggest doing it manually with the script.