You'll be needing a PROXY server in order to side side step your work's firewall. However that firewall is there for a reason - Shouldn't you be working like?
List of proxies to try (Bear in mind that your place of employment's firewall will already have a list of sites to block INCLUDING many proxy sites so you may have to try a few before you get lucky). Try these sites:
Also bear in mind when using certain words in a search engine that your work's firewall will be aware of certain words and phrases to block, like the word "Proxy" for instance. So to search for proxy sites you would have to type PRO XY. Note the space between the O and the XY. The search engine will understand what you are looking for but the firewall may not.
Once you find a Proxy site that works, type your URL (Webpage address - EG: www.facebook.com
) into the space provided on the page and click Search or go or whatever the command button says.