If you are a employ, a student or someone who is is not being able to connect to a website because some network restrictions, you can use webproxies to connect to those websites.
We are going to use a webproxy which is an opensource php web proxy. We need to put it somewhere on a webserver and by accesing it we should be able to connect to any website that is restricted. The requirements are simple: a php server with apache installed. With a simple search on Google you can find some free subdomain and hosting to host this php proxy. If our network administrator hasn't blocked the use of webproxies, we can use Google to search this usefull php web proxy called Poxy. Example: http://www.google.com/search?hl=en&client=firefox-a&hs=WOV&q=intext%3A%22PHProxy+0.5b2%22+-html+-htm+-php&btnG=Search
Be carefull, because this connection is not encrypted in any way, so anybody might be able to see what websites your browsing. You should probably not login onto websites using this method.
Resources: hak5, php web proxy