Actually, many commands requre specific syntax to get help.. it's kind of a pain to remember which ones require what.
A general summary of the commands you need to get help (beyond the windows help files):
command /?
command /help
command -?
command --help (note two dashes)
Another thing you can search for is CLI or Command Line Interface. As LiquidLen said, command prompt or command.exe (or cmd.exe) are good things to google for.
If you are working with a server remotely, search Microsofts's KB for terminal services. Terminal Services has a great deal of arcane, yet powerful commands. At the same time, there are quite a few commands you'd expect to find that aren't there. MS Thankfully does a good job of summarizing these commands in their knowledge base.