How to Finding Column Display and Internal Names in Custom list using Powershell

$web = Get-SPWeb http://peakfinders
$list = $web.Lists["Employee"]
$list.fields | select Title, InternalName, Hidden, CanBeDeleted | sort title | ft -AutoSize

As you will most often be interested in the non-hidden fields, you can add a Where to filter them:

$list.fields | select Title, InternalName, Hidden, Sealed, CanBeDeleted | where {$_.Hidden -eq $false} | sort title | ft –AutoSize