Hobby Japan (in CBD & Box Hill) have InitialD DVDs and 1:24 plastic model kits of the Akina cars (S13, 180sx, AE85, AE86) and some others like the SilEighty and EK-Type R Civic.
darK: The InitialD store is on Russell St, near corner of Lonsdale. Has lots of Japanese stuff like CDs, DVDs and collectables - toys
Cool store - but quite pricey.
I have Shingo's 'Night Kids' EG6 Civic (like my old one) and the 'Night Kids' R32 GTR (Takeshi) as keyrings (thanks to EBay). Also the BitCharG set (see below).
The manga comics are available from Alternate Worlds (Chapel St). The arcade game is lots of fun and due out on PS2 later this year (Sega release).
The movie (3rd stage) is really good. Apparently Madman are going to release the whole series (x4 I think) here after Tokyopop do a EL conversion in the US.