If I've searched for a location and found it through Microsoft Streets and Trips 2009, can I make it a pushpin without adding one of my own on top of it?

In ST 2010, you can do it for in-built POI using the following method.

1. Search for 'Space Needle' from the FIND UI
2. Click inside the POI balloon (you should see the cursor blinking inside the balloon)
3. Now click on 'Route Planner' icon from the toolbar
4. In the Route Planner pane click <Add to route> button

A pushpin will be placed on top of the in-built POI. Now you can delete the route point from the route planner pane.

But for prior versions of Streets (ST07, ST08 & ST09) the same works for online search. If you add a online search result to your route then a pushpin will be placed on the same location with the business card listing (BCL).

Cool tip, Gladwin.

This should be added to "Tips and Tricks."

I think Gladwin is trying to set some sort of "tips and tricks" record.
Good job!

I just counted the contributions to Tips & Tricks for Streets & Trips. Gladwin is leading . The #2 is S&T Team, and of course Larry & Gladwin are the team .

The tip has been added!