flickr

~$ sudo gem install flickr
Password:
Fetching: xml-simple-1.1.1.gem (100%)
Fetching: flickr-1.0.2.gem (100%)
WARNING: flickr-1.0.2 has an invalid nil value for @cert_chain
Successfully installed xml-simple-1.1.1
Successfully installed flickr-1.0.2
2 gems installed
Installing ri documentation for xml-simple-1.1.1...
Installing ri documentation for flickr-1.0.2...
Installing RDoc documentation for xml-simple-1.1.1...
Installing RDoc documentation for flickr-1.0.2...

http://www.flickr.com/help/api/