Compiling the client.cgi and using it rather than the client-perl.cgi can give a speed gain, because C programs don't need to be compiled each time they run like perl. You will need shell access to your system to compile it.
Run this at a shell prompt in the CGI:IRC cgi-bin directory: gcc -o client.cgi client.c
This shouldn't print any errors, and you should have a client.cgi program, if you try typing ./client.cgi at the command prompt you should get a few lines of output that end in, "No input found". Once it's compiled you simply need to change script_form in cgiirc.config from client-perl.cgi to client.cgi.

The identd lets a user be idented to a hex encoded version of their IP address eg: [email protected] (this decodes to 192.168.2.2), you can use the included decode.pl to decode an IP address (or work out the hex yourself :). It makes banning on the host possible at channel and server level, which makes it much easier to allow more unrestricted access to CGI:IRC. To set-up the identd.pl you need root access to the system where you have installed CGI:IRC. The identd.pl requires you to be using an inetd, i have used it with inetd but people report it works with xinetd too.

To install it, copy the identd.pl file to /usr/local/sbin (or any other suitable location). Make sure it is set chmod 755 and the path to perl is correct, add the following to /etc/inetd.conf:
ident stream tcp nowait nobody /usr/local/sbin/identd.pl
You might also need to change nobody to the user CGI scripts run as on the server - this provides slight protection from local spoofing by checking the user is correct. You can check it's set-up correctly by running telnet localhost 113 - press enter and it should print something like INVALID PORT.
This should work, but no other identd lookups will work - you can change the reply variable in identd.pl to enable other lookups. Set to reply:text it would ident all other requests as "text" (similar to nullidentd). linuxproc simply uses /proc/net/tcp to do full ident lookups on linux. forward:port forwards to the identd running on a different local port; this apparently works well with oidentd running with the proxy option.

You will need to have control of your own ircd to be able to do this.
There are several ways of achieving this, the way that works best with CGI:IRC is patching your ircd to allow spoofing of hosts, currently this only exists in the IRCD used by Blitzed (bahamut+blitzed). The way the Blitzed patch works is you add an I: line with a password of CGIIRC to match the hostmask that the connection from the server running CGI:IRC comes from. This will then read the hostname from CGI:IRC (with the realhost_as_password option enabled in cgiirc.config). Other ways include using the SETHOST or CHGHOST command found in some IRCDs combined with a bot, however this isn't very useful as bans don't always work correctly with this method (dependant on IRCD).

This little program works in a similar way to 'who', it provides a list of users logged in and where they are connected from and to.