I am working on implementing a WebDAV server for ASP.Net. Yes, I know this capability is built-into IIS6, but unfortunately, it requires that you enable WebDAV on the server, creating a big security hole. Additionally, the built-in implementation is unable to authenticate against a custom membership provider. In any event, my solution is a drop-in component that instantly enables WebDAV capabilities for any ASP.Net app.

One of the challenges when developing any app that relies on headers for passing commands back and forth (as WebDAV does), is that debugging is quite challenging. I explored several tools to sniff HTTP traffic, including a few that were implemented as ISAPI filters. I found all to be cumbersome and requiring sever-side installation. There are many IE add-ons that do this also, but since I am working with WebDAV, there is no browser in the equation. It's purely traffic between Windows and a WebDAV server. 

I had resorted to logging to a file from within my app, until I chanced upon HTTPLook. Wow! This app is awesome. It not only does exactly what I want, but it also has a simple and elegant U.I. (important to me) and has excellent features such as filtered capture etc.

My WebDAV development has become several orders of magnitude easier, thanks to this tool. And as a bonus, the app comes with a CHM help file containing the entire HTTP spec. Too cool.