Just as an FYI, I did contact Shazam on this. Response below...

Hi there

While I can say our development team are continually working on bringing the service to as many platforms and regions as possible, I’m not entirely sure when a version for n900/Maemo handsets will be available.

Full details of any new release would be made available on our website prior to launch date.

Kind Regards,

Daniel Van Damn

Customer Services