PowerShell v3 here are some of the most useful keyboard short cuts:
CTRL+N: creates a new script
CTRL+O: opens an existing script
CTRL+T: adds a new PowerShell tab
CTRL+SHIFT+R: opens a remote PowerShell tab
F1: gets help for the cmdlet that the cursor is on.
CTRL+F1: opens input assistant to provide arguments for the cmdlet the cursor is on