We are about to move into a shared building where we will be required to share meeting rooms with a few other small companies.
We currently use exchange on a small business server but will be moving to office365 for email soon. Is there any way to share a calendar resource with external users?
Have a look at Internet Calendar Sharing. It sounds like what you want, but give Exchange 2010 SP1 and Exchange Online (Office 365) Calendaring FAQ a read over (from the Exchange team blog) and see if it is what you’re looking for.
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