I just e-mailed Shazam so I'll report back when they get to me. I'm a G1 user who's not dissatisfied with Android per se (except for the Cyanogen C&D), but rather with the mediocre hardware they continually put it on. For crying out loud, I want more RAM, a faster CPU and a bigger screen.

edit: Here is the response I got back this morning
"As the N900 is running the Maemo 5 Operating system, Shazam will not be compatible when the phone is released.

Currently there’s no plan to develop an app. for the Maemo 5 OS but this could change. Full details would be added to our website prior to release."