I've pushed support for localization in mafw-lastfm's git repository. There are very little strings, so it should be quick to translate. The pot file is here and I already translated it to Spanish. If you have some spare time, please go ahead and translate it to your language. Feel free to send me the translations directly, but to avoid collisions, I'd recommend using bugzilla.
I also implemented on-disk cache during the last days. This is something that was really missing from the scrobbler, so I plan to make a release pretty soon including this.