This VBA macro code is heavily inspired by the information available at http://mutable.net/blog/archive/2006/09/02/how_to_hyperlink_to_microsoft_outlook_messages.aspx. I only adjusted the generated link text to make it suitable for use in WikidPad.
Just create these macros in Outlook, and optionally bind the macro to a toolbar button or menu command for easy access.
In Outlook, select one or more messages and execute the macro (using the toolbar button, for example). Your clipboard will now contain direct URL links to these messages in a WikidPad-ready format, ready to be pasted in your wiki page. By default, the link shows the message subject, author and received date & time. This can be adjusted in the GetMsgDetails?() function if needed.
For Outlook 2007, these links won't work out-of-the-box. That's because Outlook 2007 does not register the "outlook://" protocol handler in Windows. You can configure this yourself using RegEdit?, a detailed explanation is available over here: http://www.slipstick.com/outlook/ol2007/outlookprotocol.asp. Outlook links in WikidPad should work without problems afterwards.
Sub CopyItemIDs() Dim myOLApp As Application Dim myNameSpace As NameSpace Dim currentMessage As MailItem Dim ClipBoard As String Dim DataO As DataObject ' Housekeeping: set up the macro environment Set myOLApp = CreateObject("Outlook.Application") Set myNameSpace = myOLApp.GetNamespace("MAPI") ' Figure out if the active window is a list of messages or one message ' in its own window On Error GoTo QuitIfError ' But if there's a problem, skip it Select Case myOLApp.ActiveWindow.Class ' The active window is a list of messages (folder); this means there ' might be several selected messages Case olExplorer ' build the clipboard string For Each currentMessage In myOLApp.ActiveExplorer.Selection ClipBoard = GetMsgDetails(currentMessage, ClipBoard) Next ' The active window is a message window, meaning there will only ' be one selected message (the one in this window) Case olInspector ' build the clipboard string ClipBoard = GetMsgDetails(myOLApp.ActiveInspector.CurrentItem, _ ClipBoard) ' can't handle any other kind of window; anything else will be ignored End Select QuitIfError: ' Come here if there was some kind of problem Set myOLApp = Nothing Set myNameSpace = Nothing Set currentMessage = Nothing Set DataO = New DataObject DataO.Clear DataO.SetText ClipBoard DataO.PutInClipboard Set DataO = Nothing End Sub Function GetMsgDetails(Item As MailItem, Details As String) As String If Details <> "" Then Details = Details + vbCrLf End If Details = Details + "[Outlook:" + Item.EntryID + " | " + Item.Subject + " (" + Item.SenderName + ", " + Format(Item.ReceivedTime, "yyyymmdd | hh:mm") + ")]" + vbCrLf GetMsgDetails = Details End Function