You could use a unix utility that would do a scan based on TCP commands. Or you could do a high level ping scan. If you know the machines are all going to be friendly you could try to connect to a given port.. Um, how big is your network?

Why not check out nmap at insecure.org? Something like that can help you especially if you want to check the security of those hosts. You can also catch machines which have been set up to be quiet on your network, something which I don't think I'd trust ping to do. I know it's kind of like asking for a match and being given a tanker full of gasoline so be careful with the stuff. You should be able to parse the output file.

Probably all you need to do is write your own script to ping a small company network for something short and sweet. But know that professional tools like those above are available.