I too am looking for a better way.
After just returning from Yosemite with some 300 pictures to catalog, this is what I'm doing till someone has a better way, and not wanting to spend a longtime in the darkroom, so to speak. At this point I do not want a GPS logger (one more thing) and something attached to my D300.
I first sort my pictures in PM as to a general location and put them in folders. I use Google Earth + a plug in from "Ogle Earth" called "Crosshairs" and another small program called "Geotagger vr 1.2. Open Google Earth and find the location where a folder of pictures were taken, say, "Mirror Lake", move Google Earth so the crosshair is over the general location. Now, open that folder and select all the photos and drag them over the icon of Geotagger and I'm done. Yes, all those photos within that folder have the same GPS location but at least I'm within a few hundred feel. For any few special photos I can get more precise GPS by using Google Earth.
Not pretty but a least their tagged with something and in PM.
Stoqwell