Working with ip addresses and address space

Hi all, anyone know of any good pre-written classes or functions to work with IP address space? I'm looking for things which can verify correct notation of IP addresses (fine, that's easy enough), but also verify things like network addresses, broadcast addresses, and work out subnet masks when a start and end IP address is given... Any ideas? I'm sure I can just write my own... But it's going to save me allot of time if something like this is out there already for me to use. -- me