[aprssig] Mic-E to lat/lon conversion widget?

[KC2MMi]

Does anyone have a widget available so that I can place a Mic-e encoded
position in, and get the human-readable lat/lon back out of it? Or even
better, a widget to decode the entire Mic-E packet?

A small Windows applet, a javascript on a web page, an Excel
spreadsheet...pretty much anything so that I can do the decoding
conveniently?

I was hoping not to have to write something from scratch for this, math is
not my forte.<G>