They aren't available as a separate module. There's two options that I've found :
The first is simply to use a remote session from PowerShell. You'll need to make sure that you import the required module once connected, but other than that it works fine. Of course if you want to run a script against the SharePoint box, then just use Invoke-Command
The second, is to use implicit remoting, where you actually export the commands from the remote computer onto your own computer. PowerShell does some nifty stuff, setting up a proxy for these commands so that they are routed to the target box dynamically. Take a look at the help for Export-ModuleMember to get a better idea what's involved. I'm sure I've got a script kicking about for this somewhere, will do some digging.
NB. The second option doesn't always work as expected so I'd usually favor the first option for remoting.