Exchange 2010 – set rights with powershell
Mailbox:
set-mailboxfolderpermission -Identity testuser:\calender -User cl -AccessRights editor
Resource Calender:
Add-MailboxPermission –Identity testresource -User all-usersgroup -AccessRights FullAccess -InheritanceType All
Public folders:
Get-PublicFolderClientPermission -Identity “\firm1\firm1 calender”
Add-PublicFolderClientPermission -Identity “\firm1\firm1 calender” -AccessRights PublishingEditor -User testuser