While technically true, practically speaking this probably doesn't help so much as the gain in depth of field from the shorter focal length will be given back by having to move closer to the subject (if even possible) to retain the same framing (magnification). Both factors happen to affect the DOF (in opposite directions) in proportion to the square of their value (from the equations I have seen). There are a few interesting demos of this phenomenon on line which, while appearing somewhat flawed in their descriptions/execution, do make the point. If you keep the distance from the subject and aperture the same then absolutely you will have a larger DOF with the shorter focal length - but you will also have the subject be a much smaller portion of your field of view - and hence lower resolution. No magic bullet here and really just a matter of finding your own "sweet spot" between an acceptable DOF and resolution/magnification for what you are trying to do. On a side note, one thing that does change noticeably between short and long focal length lens using the same subject framing (e.g. different distances to subject) is the "quality" of the out of focus material - you get a much "softer" look with the longer lens... at least from the demos I have run across. This is despite the observation that the DOF (as defined by the in focus distance) remained essentially unchanged.
Sorry for the sidetrack but I have been digging into this lately since several people started posting great macro shots on here ๐ค