Need help with NDS Flash Card & Linkers

I was looking at

http://nintendo-ds.dcemu.co.uk/ninte...faqguide.shtml

at the list of stuff needed for NDS. What I'm wondering is which of those things would I need to be able to play GBA roms (commercial and homebrew), emulators (although I assume they would come under GBA/NDS homebrew?) and NDS homebrew games? For now I want to be able to do that, but I also want to be able to buy the rest of the stuff in the future (when I can afford it) so I can also play commercial NDS roms. I've been looking at so many different cards and linkers and I'm getting very very confused...:confused: Hope someone can help!

for just gba roms and emu's you won't need a superkey or passkey etc. but you will need a supercard or M3 adaptor with the memory card to go in it and that's it apart from if you don't have a card reader then you need that aswell. Visit Divineo.com and buy from there they are under backup/development in the nds section on the chinese and american sites.

Ok I'm getting a Nintendo DS, a Game Boy Advance SP and an EZFA Realtime 256Mb card and USB lead. What else would I need to add to that to be able to play NDS roms? I know the EZFA Realtime card works on the NDS.

By the way, slightly off-topic this, but I'm trying to drag some Z80 spectrum roms into the Foon emulator, and it doesn't seem to accept some or them, even if they are Z80 roms of proper games...it says "not a valid 48k rom" or something. Any idea why?