how to setup an onscreen speedometer?

I've been tinkering with it, & so far I've been able to come up with a timer by creating 2 Scene Behaviors (called "Timer" & "Draw Timer") and creating a new Game Attribute ("Time"), but I can't figure out how to get the actor's actual current speed (in pixels per second). Any help?

There are blocks for X-speed and Y-speed, but unless you're just moving left/right/up/down you'll need to use trigonometry to find the overall speed.  I don't know what the unit of measure is.

Pixels per second, I believe is the measurement that Flixel uses. Having Box2D integrated might alter that though because it measures in Meters (per second). I'm not sure what the scale is of pixels to meters.