2 companies separated by the Atlantic ocean and a WAN link, 2 separate AD domains, 2 separate mail domains. Exchange 2007.My question is what is the best way for a user in one domain to view another user's calendar in the other domain? Resource domain?I'm an Exchange newbie.

Do you want to see their entire calendar, or just if they are free/busy? If the later, you can use the availability service. Is there Exchange 2003 in the mix? You can read here if so, or if you'd like to use the interorg replication tool.

Oh, and if you want to use something custom, you can build an app using Exchange Web Services. Exchange Calendaring Tasks http://msdn.microsoft.com/en-us/library/bb204087(EXCHG.80).aspx

Users will want to see the other people's entire calendar. There is no Exchange 2003.Are there any 3 party apps that make this easier?