From the Bing Blog:

We’ve just released an update to the Twitter Maps application in the Bing Maps Application Gallery. NOW, you can embed our Twitter Maps functionality into your own web site. This means you can be cool by having a Bing Map on your web site, blog, favorite social networking site with the Tweets you care about. And, WOW, it’s super easy.

Here is a sample with Tweets from SXSW

You can do this in four easy steps:

1. Select the map location either fixed (centered on a specific point) or anywhere (moves the map as the Tweets come in).
2. Specify the dimensions of your map (height and width).
3. Add search filters. These will be carried into the embed form if you’ve specified them to filter only tweets that meet your search criteria.
4. Copy/paste HTML into your web page.