I have a neat little free app for my Blackberry called GPS Logger II that makes it very easy to tag your photos in Lightroom. You just start GPS Logger II when you head out to shot (make sure to take your phone with you of course) and then you can export the recorded path in .gpx and a few other formats as well. As long as your camera time and the phone time are matched, you can merge the path data with your photos in Lightroom and they are tagged. I'm sure there's a similar app for other phones as well. Here's a link.