If you're talking about getting the IP address of the browser for the particular connection you are dealing with it is just:

use Apache2::Connection; 
use Apcache2::RequestRec; 

my $client_ip = $r->connection->remote_addr;
[download]

If you're wanting all of the IPs currently connected to all of your Apache children, then you are going to need to write a special handler that will log ( to a file or database ) when a connection comes in, and then remove it again during a Cleanup phase.

If you have actived the status-module in your Apache-server, you can see which requests are being serviced and which IPs are linked to these requests.

Apache2::RequestRec::connection gets you the connection record for this request and the Apache2::Connection::get_remote_host gets you the client's IP or host name.

http://httpd.apache.org/docs/2.0/mod/mod_status.html This one can be a solution for me but I cant see how to access this information as the Apache2::Status show me things about the Embedded interpreter status, and aparently cannot return the current hosts and requests being processed Some idea? Thanks

http://search.cpan.org/~mjh/Apache-Scoreboard-2.08/lib/Apache/Scoreboard.pm I continue making tests and I now I found this module from CPAN, wich is an API to the scoreboard for modperl2, didnt made the tests with it but probably is exactly what I was looking for.

An external solution would be to use lsof, as demonstrated here

Whether this is appropriate depends on the problem you are trying to solve.