LOL. I'm sorry for sounding rude, but your post strikes me as funny -- the type of question you are posting on board primarily made for folks who work in the IT field, many members being IT managers or even CIOs and you want us to help you skirt the policies of your IT department? LOL
Well the answer is there is software that does what you want, but its just not ethical for me to help you directly with it.
But realize that it depends how your company/IS department does their filtering too -- like if they filter by IP address for example, there are ways for THEM go skirt YOUR solution of merely hiding the domain name.