Anyone know of a browser that can log the individual HTTP requests - i.e. - all the gets, posts, all the headers, etc while you are browsing?

I am doing some security analysing for a company and their web apps could be vulnerable if someone were to know the address of the page they get redirected to and then redirected from right away (ok - that was as clear as mud) - like this:

Login + Password form passes data to a program that tests to make sure Password is correct. If so, they get redirected (via a "Location: " header to a page that will process their data in the background and then right away will again redirect them w/ header to a "Successful" page. In other words, using a normal browser it would look as though they jumped from the form to the successful page (even though they acually just hit a bunch of pages).

The problem is that if you go directly to the page that will process the data, it will do it without any security varification. Just wondering if there were browsers (or plugins?) that would either log this in some way or tell you it was happening.