Project @ sf.net
(Here be the sourceforge logo)
Philtron is written in PHP, which means it's cross-platform and it's safe from buffer overflows and similar bugs, which can appear in low-level languages (c/c++). On the other hand the built-in regular expressions make implementing HTTP and parsing incoming and outgoing traffic very easy.
The proxy will fully implement HTTP/1.1 protocol, which means it can
download web pages and their requisites (images, flash movies etc)
fast and intelligent, even superior than some of the existing browsers
(for example Internet Exlorer doesn't use pipelining - one of the
advanced features of http/1.1 which greatly improves speed on
image-heavy pages) and will help http/1.0 clients communicate faster
with the http/1.1 servers (for example wget works faster through Philtron).