PCBTemp.exe
Which looks at the relationship between trace current, geometry, and temperature rise of PCB traces.
**broken link removed**
Wiregage.exe
Which converts between trace geometry (width and thickness) and equivalent AWG wire gauge. It also calculated trace resistance at a given length and temperature, and voltage drop across the trace for a given current.
**broken link removed**
Which CAD tools have this capability built in?
The Sigrity tools have this capability, but USD 60,000.00 is a bit much to pay for this capability.
Cadence Allegro doesn't have this capability as far as I know.