nmap is a really excellent network tool that most folks are familiar with. I find that I tend to use it to first discover hosts on a network and then to get more specific information from a targeted node. The first part of that discovery is the ping sweep, which can be done thusly.
nmap -sP 192.168.1.1-254
Pretty simple. 192.168.1.1 is the start IP and 192.168.1.254 is the stop IP. nmap will ping every address in that range and return the IP of hosts that respond.