Are you talking about in the terminal? If so, then the command for that is niutil. Also related are nidump (which will print out the stuff in the NetInfo domain), niload (you can use it to load properties from a file), nifind (can use it to find instances of a property), and nigrep (can use it to search with regular expressions).
I have to say though, it's a lot easier to use the NetInfo application in /Applications/Utilities to mess with all of that than using the command line programs.