ie n64
if so how do i configure it do i have to instal a emulator etc?:

also can ROMs access the gba cart for certain games like pokemon diamond where you transfer pokemon from the gba ruby game to the ds card

As far as running emulators I'm not sure but I think they are working on emulators that run on the DS. Not sure how N64 will work though. I'm still surprised they manage to get PSX games to work on the PSP.

From what I can tell the NDS games you load on any slot-1 flash card like the R4 should function just the same as it would if you used the real cartriage. I know that at least the games the use wifi work.

thank

Yes, there are emulators that will work on the R4DS, but there are currently no N64 emulators. There are emulators for NES (nesDS), SNES (SNEmulDS), SMS/GG (DSMasterPlus), and Genesis (PicoDrive).