A quick hint: If you tag your photos with their GPS location (in the EXIF data), Flickr can put them on a map for you.
But it doesn’t do it automatically.
You need to enable it using the option on this page:
http://www.flickr.com/account/geo/exif/
Even then, it only does it for photos you upload from that point forward. I haven’t found a way yet to get it to make use of the lat and long I’ve been including in most of my photos for the last few months.
Still, this is a good start. I’ve re-uploaded my last batch and you can see the map here.
Many thanks to Chet.
Update: Here’s a script that can use the EXIF data restrospectively. Fabulous! Many thanks to Sam Judson!