Am I correct in assuming that it is possible to send any type of UDP packet to the broadcast address (eg 192.168.1.255) and all machines on the net 192.168.1.x will receive the data? I need to send the exact same packets from one machine to several others on the network, it costs more processing power to route packets to several hosts at once in the app I am using.

UDP is connectionless. It could be that if you set up your network commonly it would do that. UDP can be blocked by many things.\ 5.4 The Transport Layer There are two primary transport layer protocols: Transmission Control Protocol (TCP) and User Datagram Protocol (UDP). They provide end-to-end communication services for applications. 5.4.1 UDP This is a minimal service over IP, adding only optional checksumming of data and multiplexing by port number. UDP is often used by applications that need multicast or broadcast delivery, services not offered by TCP. Like IP, UDP is connectionless and works with datagrams. I read it wrong and answer it wrong too. So get off my case you peanut.