Because of the flexibility of the system, there have been a number of options around for a while that have allowed users to geotag their photos. None of them have been quite as simple as Flickr have just made it though. And it's great to see that the guy that built the first geotagging mashup of Flickr and Google Maps - Rev Dan Catt - was actually the person that Yahoo recruited to build up the geotagging functionality within the site itself.
The new geotagging system is really easy to use, it's functional and it's pretty at the same time. It also has a geotagging API that developers can plug into if they wish.
The thing that surprises me is the lack of support for GeoRSS in their feeds. With all this location information flying around (1.2 million photos geotagged within the first day) it would make sense to include that geodata in the RSS feeds from the site. I'd really like to be able to pull geotagged photos from my Flickr stream into my geoblog and photos section over at geodan.org and have their location information automatically assigned based on the information stored against them in Flickr.
You can also see my map of photos on Flickr.