You can now use the Picasaweb interface to place each of your photos on a Google Map! One they're placed, clicking on an image will navigate the map to its location. You can also play an image slideshow that will cycle along each position on the map.
Also, simply entering a 'location' for each album will place a marker on a map on the Album List page, so you get a world map of all the locations you've got an album for. Same thing works for geolocated pictures in an album (bottom left) and for each photo your viewing (bottom right).
(edit 10:06) The link from the Google Blog post doesn't work, but mobile Picasaweb is available via this (http://picasaweb.google.com/m/) link. It's clean, fast, and simple just as you'd expect. The main page lists your albums with a thumbnail, the album pages show up to 12 thumbnails and the image view shows a reduced size version of your picture. You also have access to your 'favourites'.
At the time of writing, the mobile Picasa page was not yet up, I'll update this post once I've had a chance to experiment.
Now excuse me as I geolocate every photo I've ever taken.
(Note 10:06) Photos you geotag using desktop Picasa will be automatically geotagged in Picasaweb - but only if you upload them from now on. Any photos you previously uploaded to Picasaweb will not automatically display their location.