Share calendar between users on different Exchange servers/Different Domains

I am looking for a simple 3rd party application which will let me share my calendar in my mail account on my Exchange server with 2 people on a different exchange server/different domain.  Another option is to share my calendar on my outlook or exchange server with my outlook account on the other exchange server.  I do not want to use microsoft products because they only let you see free busy data.  Also this isonly for 1 user so I do not need some enterprise product which costs many hundreds of dollars.  They need to be able to see, change and modify appointments for me and I need to be able to do the same for the appointments added to my calendar by them.
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No need for any 3rd party tool. It is inbuilt in your outlook.
If you domains are part of the same forest and same exchange organization then this is possible. All User A (who wants to share his calendar) has to do is to add User B to his delegates list in Outlook (Tools-> Options -> Delegates Tab)
The easiest way to check this is to see if users in both domains appear in the global address list.

If both are in different forests. Please check in a logical way and try.  Is that you create an account for UserB in DomainA (UserA's Domain). Lets account UserBA . UserA then delegates  calendar permission to UserBA . Then UserB can use Outlook Web Access (of DomainA) using UserBA credentials to see the calendar. If OWA doesn't work. You can create another profile on UserB's computer to connect to UserA mailbox. When configuring this profile, ensure that the user is always prompted for a password.

If you desperately need to use 3rd party tools, please check for the below link:


kaparaAuthor Commented:
Different domains and they need to do this directly from outlook on their machines.  Also I just found out that I cannot use a 3rd party tool which uses PST to send the changes since they are Echange users and do not have PST files.
kaparaAuthor Commented:
Holy Moly.........  I just tried GsyncIt from google.  Lets me synchronize 1 gmail calendar with multiple Outlook clients.  License is 10 bucks each!!!!!!!!!!!!!!  I think I am dreaming...pinching myself. works.  Just tested.

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