23 is a lot like flickr. Almost a clone, even down to the UI and feature comparisons.
The service is free, for up to 15 MB of uploading a month. 29 EUR gets you an unlimited bandwidth account.
The things I like best about Flickr right now are the “sets” (23 calls them albums) and the uploader tool which takes the pain out of uploading many pictures at once. 23 needs a similar…