I had a work colleague install Garmin on my N95 here for Saudi, so had all the local maps and it worked fine. As it was on my memory card, it's still there in my N97, but couldn't get it to run properly. e.g.
It starts up fine on the N97, screens are ok, no problem, but when trying to enter an address, the screen prompts require a hard key press, and tehre is no corresponding button, so I can't get it to the next stage.
Not sure which version of Garmin I have, will check, maybe its an older one?
Just note that the current version (5.00.50) will have graphics issues in widescreen/landscape mode (it will overlap). Garmin is trying to fix this issue apparently.. (this only appears on N97 but is ok for 5800 though).
It does work still - just make sure you have it upright (looks a bit stretched out and weird - but does work).