Tip: Opening a new tab is useful to open a new clean environment or to establish a session on a remote computer.
To open a local Powershell tab : Control + T
To open a remote Powershell tab : Control + Shift +R
To rename a tab where you are :
$psise.CurrentPowerShellTab.DisplayName = 'Dev'
To rename a remote tab, you need to do that from a local one (where the first tab is [0] ):
$psise.PowerShellTabs[1].DisplayName = 'Remote-Server01'
Note: With the great ISESteroids add-on (Tobias Weltner), you can easily rename tabs (right click on the tab).