Squid is a high-performance proxy caching server for web clients,
supporting FTP, gopher, and HTTP data objects.  Unlike traditional caching
software, squid handles all requests in a single, non-blocking, I/O-driven
process.

Squid supports SSL, extensive access controls, and full request logging.  
By using the lightweight Internet Cache Protocol, squid caches can be 
arranged in a hierarchy or mesh for additional bandwidth savings.

See /usr/doc/squid-3.0.STABLE21/README.SBo for configuration help.
Note that the default squid.conf and /etc/logrotate.d/squid files have
changed in this release, so be sure to merge the changes into place.