I have Exchange Server 2003 and I want to see free/busy schedules for the users in SharePoint. Is it possible?
I want to do this in SharePoint 2010.
There is no out of the box feature for this, so you will have to go with custom code.
With Exchange Server 2003, the API was somewhat limited compared to now. Here is some sample code for displaying free/busy info on a web page that you might be able to incorporate on a Site Page in SharePoint 2010: http://msdn.microsoft.com/en-us/library/ms992522(v=EXCHG.65).aspx
With Exchange 2007 and 2010, there are some web services available: http://msdn.microsoft.com/en-us/library/aa494212.aspx
See http://msdn.microsoft.com/en-us/library/dd877037.aspx for a list of all the web services in 2007.
Depending on your specific needs, you may have to do some iteration on the SharePoint page.
If you are using Outlook Web Access, there are some web parts available for your SharePoint although I don't think they will cover what you are looking for. But this Calendar Plus web part from KWizCom may be of help although I cannot find evidence that it is supported in SharePoint 2010 as of yet: http://www.kwizcom.com/ProductPage.asp?ProductID=175&ProductSubNodeID=176