How to emulate Outlook enviroment???

System.DirectoryServices , Provides easy way to access and searh the ADS, all that you will need is to have a Username and Password.

Sample Code:

Declaration
using System.DirectoryServices;

DirectoryEntry oDirectoryEntry = new DirectoryEntry();
DirectorySearcher oSearcher = new DirectorySearcher();

SetUp

oDirectoryEntry.Username = "XX"; \\Change this to real values
oDirectoryEntry.Password = "PWD"; \\Change this to real values
oDirectoryEntry.Path = "LDAP://" + sDomain + ".MyCompany.com/DC=," + sDomain

Query

oSearcher.SearchRoot = oDirectoryEntry;
oSearcher.Filter = "(&(objectCategory=user) (mail=" + psUserEmail + "))";
oSearcher.SearchScope = SearchScope.Subtree;
oSearcher.PropertiesToLoad.Add("sAMAccountName");
oSearcher.PropertiesToLoad.Add("displayname");
oResults = oSearcher.FindAll();

You could also try to find the Calendar webservice provided by Microsoft. I cannot find the weblink now! This uses HTTPWidget to access the Microsoft exchange server , similar to outlook webaccess.

as far as UI goes infragastics, provide some useful UI controls similar to outlook.