My DSLR camera doesn't have GPS, so normally all my photos would not include the location of where I was when I took the photo. I used to use the Eye-Fi card that did geotagging, but that is no longer supported in the new "mobi" line. I could get an external GPS unit for my camera, but that sounds cumbersome and would only work with that one camera.
Since I already track everywhere I go, I figured I could use this data to geotag my photos when I upload them to Flickr. It turns out, …
Lightroom can import .gpx logs to automatically tag photos. But looks like you’re not someone who would use Lightroom :)
About the timezone problem — do you change the time on your camera when you travel to a different timezone? Why? Why not just let the camera’s clock stay in home time or UTC?