Get access to edit sealed, read only columns in SP2010
When using SharePoint content migration software this is really useful because if the column is read-only and sealed you can't write to it! (Unless you do a few tricks... )
Using SharePoint Management Shell (2010):
#Get the web, list and column objects
$web = Get-SPWeb
$list = $web.Lists[""]
$column = $list.Fields[""]
#Change the readonly and sealed properties and update objects
$column.ReadOnlyField = $false
$column.Sealed = $false
$column.Update()
$list.Update()
#Give us the new column settings for our reference
$column
$web.Dispose()
Click here for more SPField properties.