a multi-purpose application level gateway, or a proxy server which runs on multiple platforms (Unix, Windows, MacOS X and OS/2). DeleGate mediates communication of various protocols (HTTP, FTP, NNTP, SMTP, POP, Telnet, SOCKS, etc.)
an interactive HTTP/S proxy server for attacking and debugging web-enabled applications. It operates as a man-in-the-middle between the end browser and the target web server, and allows the user to intercept, inspect and modify the raw
an application that uses the power of Google's global computer network to make web pages load faster, local cache, prefetching, data compression. Currently a Google Labs product. (probably good for very slow connections and as a general proxy)