Normally the set-up for a transparent proxy are fairly straightforward, but something seems to have changed with the 3.0beta and it is poorly documented.
The usual option in squid.conf for transparent proxies don't seem to work in 3.0.
Without them set, the port forward works, but it seems to strip off the http://foo.bar/
part of the request and only passes the sub-path /foo-dir/files.html which of course causes an error.
Has anyone found a decent how-to for Squid 3.0 yet? Squid-cache.org is still focusing on the 2.5 series.