Yes to the first question. Don't know to the second.
In most versions of Outlook, if you go through File-Open, you can select a .PST file. It will show up as another folder or folder tree under your main Outlook folder tree. You can then copy from one folder to another (e.g., Tasks to Tasks).
As to the second, in the Palm environment, Chapura's PocketMirror allows you to draw from multiple calendars and other folders. I'm not sure about the PPC/Activesync environment.