that would be a network setting that you admins put up.. so that you cant check you email..

Try to access it with annoymizer or some other proxy.  Make sure you have permission for it, as this is a fireable offense in some companies (circumventing company blocking that is)

Here's a proxy list:

http://www.atomintersoft.com/products/alive-proxy/proxy-list/

Can search google for more "proxy list"

If I understood you correctly you are trying to get to an HTTP based email server and for some reason you cannot?  

Proxying should work for you, only thing is that you're going to have to muck around with many of these "free proxies" until you find one that works.

When I was down at DELL in Texas for training, they had MSN messenger blocked, which I use to talk to my wife all day when I'm at work...Proxies did the trick.