There is no specific tool for this, although the IP network browser can detect this on an individual host basis.
The IP network browser will show you any open ports under TCP connections, as well as what services are running under Services. This of course assumes you have SNMP access to the group of servers you want to scan.
You could download one of the many free tools available on the Internet which can scan for web servers. You would, however, have to know what port the server is running on to detect it.
