You can do what Justin answered or you can create your own alias for the command. it depends if you need to use the command often throughout a session. If you don't, just listen to Justin. If you do, aliasing isn't a bad idea.
sc.exe executable that you would like to use. (We'll assume it's in the root of your C:\ drive for now.)
Create the PowerShell alias with the following command:
Set-Alias <What you want to use as an alias> <Path to executable or one of the commands Justin proposed>
Set-Alias sc2 "C:\cs.exe"
These aliases will disappear when you close PowerShell, export them like so:
Then import them when you need to use them (disregard all the errors that show, these errors are due to the fact that PowerShell tries to restore all aliases, including those that are built-in. Of course, these already exist so they are ignored.)
More documentation on PowerShell aliasing available on MSTN.