Recently I had a need to monitor how many TCP connections a single process keeps open. I use Nagios as a monitoring software. After spending some time looking for such plugin I decided to write my own.
Here it is, accessible via Nagios Exchange. It uses netstat to figure out list of connection, unfortunately it needs sudo to get such a list (I would be very happy if someone could point me to a way of listing such connections without super user rights). Anyway, here it is if anyone would like to try it.