That's right, from ESRI!
We recently made the move from ArcMap 9.3.1 to 10, and darned if there isn't something in there a lot of us will like!
Formerly available only with the high-priced arc seats, ArcInfo and ArcEdit, the Export to CAD function is now part of the ArcMAP package.
Right-click a layer in your project's table of contents, or in ArcCatalog, and select Data, then Export to CAD, and up pops the Export to CAD tool. Note that the dialog allows you to continue selecting layers in your project, or even feature classes in geodatabases, even shapefiles (yuk) to include in the output drawing.
And that's drawing, not just DWG, because the command will also save to Microstation DGN format.
The function may be called programmatically (from your own code, dude!) where it actually offers more capability - like indluding the feature class definitions, attribute data, and even the coordinate system.
I'll be playing with this a lot in the near future - stay tuned for more as I get this puppy trained!