I have LIVED by these instructions for creating a tickle file in Outlook since I first saw them in 2005: http://www.360doc.com/content/07/0619/00/10186_566463.shtml
Summary: you customize an inbox view that only displays messages w/o a due date and the messages whose due date is today or earlier. You make the due date field editable, so if you get a message that you can't deal with until next Tuesday, you can type Tuesday into the due date field, whereupon it disappears (but is still in your inbox!) only to magically reappear on Tuesday! That way, your inbox only shows things you can handle right now.
I just got switched to Outlook 2011 for Mac and don't see any way to do this. I'm about to crawl out of my skin!
This answer re: creating a smart folder w/ an advanced search helps, but there doesn't seem to be a way to OR the fields, like "due date = no date" OR "due date < today." http://superuser.com/a/201855/121520