Finding site column used anywhere in your web application

Little powershell script to find out where your fields are currently being used in the web app

$solutionWebApplication = "http://yourSPurl/"
$fieldTitle = "ActiveConfig"    #DisplayName
$fieldGroup = "Custom Columns"
$spAssigment = Start-SPAssignment    #Use to dispose SPWeb safely
$spWeb = Get-SPWeb $solutionWebApplication -AssignmentCollection $spAssignment     #Get SPWeb Instance
foreach ($field in $web.AvailableFields)
{
 if($field.Group -eq $fieldGroup -and $field.Title -eq $fieldTitle)
 {
  $field.ListsFieldUsedIn() | ForEach-Object {
   $web = $site.AllWebs[$_.WebID]
   $list = $web.Lists[$_.ListID]
   Write-Host "Web:" $web.Title " | List:" $list.Title " | ListUrl:" $list.RootFolder.Url " | StaticName:" $field.StaticName " | FieldID:" $field.ID
  }
 }
}