You can right-click the thumbnail in Bridge, and the context menu will offer a choice of Open In Camera Raw, which will be hosted by Bridge.
The recent book, Real World Camera Raw with Adobe Photoshop CS3 by Bruce Fraser and Jeff Shewe, spends quite a few pages discussing the several ways of accessing Camera RAW from both Photoshop and Bridge, with different implications for each. In addition there are ways of accessing Camera Raw without actually opening it.
Any question I could come up with about Camera RAW vis-a-vis CS3 and Bridge is addressed in this book in a clear fashion with enough of an explanation of the technical aspects of it to provide real "Aha!" experiences.