Squid proxy server is an easy-to-setup and fairly secure piece of software. It supports SSL, HTTP, FTP, caching of DNS lookups and offers you extensive administration features such as acl's, site "blacklisting" & content filtering.
If your server runs a linux/unix distribution, you can get the latest tarball from
http://www.squid-cache.org/ (current version is 2.6 I think). There used to be a windows port avaliable on SourceForge (
link) with administrative features, called the "Squid configurator" or something. It used to work quite well too.
Alternatively you could setup a VPN between you and your server and configure your firewall to forward all requests from SOURCE {HOME-IP} on port 80 on your "virtual connection" (eg. the CHAP connection OpenVPN sets up) to the live internet connection (probably eth0).
The short and sweet is that unless you have fairly extensive knowledge of your operating system and the proxy software, you are unlikely to be able to find a "quick-and-easy" method of achieving what you're looking for.
If I was allowed to, I'd offer you my services (at cost), but the forum rules prohibit it.
If you're looking for an engineer to help you setup your system, you should post a request in the
Employment Opportunities section.
Good luck!
Regards,