Capturing Another Application's Network Traffic

[Mkz]

If you're looking for a ready-to-use tool and not develop your own code, another one you can look at - also WinPcap-based - is YATT (http://www.pocketsoap.com/yatt/).
It's pretty straightforward for seeing HTTP traffic, and doesn't require any changes in the target app. In the same site there are also a couple more tools for slightly different needs (SOAP, XML, ...)

As for the admin rights, after installing you can configure the WinPcap driver to start on boot, that way the user doesn't have to be admin to start it on-demand. Check here: http://www.winpcap.org/misc/faq.htm#Q-18