Japan GPS

Heard that Japan GPS is really neat. Other than a international driver's licence, what do i need or what do i need to know? Is there a centre or driving range whereby I can try out the GPS? I'm from right hand driving country, any difficulties with that? Also, I heard that the GPS in most rented cars are Japanese?
Thanks!

Yeah the GPS unit will be in Japanese so get a Map book in english too and you'll be good to go.

The Japanese drive on the same side of the road as the UK and also their cars are RHD aswell so you will only need to fill a form out to get your permit

Thanks murraymint, any tips on cheap car rentals in Tokyo? Or if I should get the car rental at the airport instead? And also, if i pay be credit card, does that cover insurance or do I have to get my own insurance?

The following service (especially the Mazda outlets) still offers the cheapest rates in Japan that I am aware of:
http://www.japan-guide.com/ad/coocom2.html

I bought Japan maps from http://uud.info/en/navi/ and loaded them on my US-made Garmin nuvi. It seems to be working fine for GPS in English. Garmin doesn't have any official maps for Japan.

I bought the same map from http://uud.info/en/navi/ for my Garmin and it worked fine from city to city but it had some minor difficulties to route me to the station within the Kanazawa city limits but that was no real problem.