A simple VB solution to search for Users in Exchange via Outlook

ResolveRecipient.vb

Function ResolveRecipient(strSearch As String) As Outlook.Recipient
	If String.IsNullOrEmpty(strSearch) Then
		Throw New Exception _
		  ("Empty string was given to ResolveRecipient Function.", _
		  New NullReferenceException("strSearch at ResolveRecipient IsNullOrEmpty"))
	End If
	Dim App As Outlook.Application = New Outlook.Application
	Dim NS As Outlook.NameSpace = App.Session
	Dim rec As Outlook.Recipient = NS.CreateRecipient(strSearch)
	If rec.Resolve Then
		Return rec
	Else
		Throw New Exception("Unable to resolve Recipient")
	End If
End Function

At this point you could gather information on this way:

Dim strAlias As String = rec.AddressEntry.GetExchangeUser.Alias
Dim strBusPhone As String = rec.AddressEntry.GetExchangeUser.BusinessTelephoneNumber
'[...]