I had written a while back regarding the steps to be taken to set calendar options for resource mailboxes in Exchange 2007, read it here. The process was to use the shell command "Set-MailboxCalendarSettings". Few options could be set using OWA in 2007.
We don’t have this command in Exchange 2010 anymore. More options for the resource mailboxes have been exposed in the 2010 console anyway. But if you are a powershell person and have used "Set-CalendarSettings" in 2007, the equivalent command in 2010 is "Set-CalendarProcessing"
The command to autoaccept meeting request is Set-CalendarProcessing -identity "resourcemailbox" -AutomateProcessing AutoAccept
In order to add resource delegates, run
Set-CalendarProcessing -identity "resourcemailbox" -ResourceDelegates "user"
Most of the options you need are exposed in the resource mailbox properties. I will provide snapshot of the different tabs, as the options are self-explanatory.
In short, if you are a powershell person, remember that the commands are different in 2007 & 2010.