I'm posting a few links for proxy use. This may have been done already.
One should only use a proxy if it comes back as being "Proxy is high anonymous (elite)" -if your concerned about privacy. I personally would avoid any US based proxies as well. It would be better to have it in a foreign country. Reason being, if the proxy server keeps logs -the time delay between unfriendly nations might might be long enough that these logs no longer exist. Keep in mind this is only for inet surfing habits. In other words, proxies will not save you from illegal activities. Your only trying to blur the tracks on surfing habits, etc.
You can check your ip from "stayinvisible" in the main menu. I would advise against using the "Check Proxy" for anon status with the "stayinvisible" site, more beneficial to use the second link.
You can also chain anon proxies.
An example:
[user] ---> [proxy1] ---> [proxy2] ---> [proxy3] ---> [web site]
http://proxya: port/http://proxyb: port/http://proxy C: port/http://proxyd: port/
Chaining and switching of proxies every 30 seconds or so is great, but it is likely undesirable for small bandwidth users. Proxy use is valuable against Spyware and Adware.
http://www.stayinvisible.com/index.pl/proxy_list http://www.checker.freeproxy.ru/checker/index.php http://ip2location.com/ http://www.samair.ru/proxy/ http://www.whatismyip.com/