Jeffrey Friedl, yes, the same Jeffrey Friedl that put out the Online
Exif Metadata reader, has now released a
Geotagging plug-in that works directly within Lightroom.
His plug-in reads a GPS unit's track log, then extrapolates the
location for each specific digital image based on the time it was
taken. Although that's the same basic mechanism many other geotagging
programs employ, Friedl's plug-in allows you to move move the process within Lightroom, minimizing the steps it takes to geotag your images.
Read his full blog entry on the Lightroom Geotagging Plug-in for a link to the download.