where can i download neo geo cd iso and is there an emulator to play them?

Yeah go to www.mame.dk they have ALL games for the neogeo. I believe they have CD ISO's, not sure tho..... As for the emulator for cd, go to www.zophar.net

is there a neogeo emu for dc yet?

It will never be possible to emulate the Neo on the DC. There is simply too much power and the Dc just doesnt have enough speed. The thing cant even emu a SNES 100%. Dont hold your breath for a NEO emu

No, its memory limitations. Not speed. The DC is more than capable to run any NeoGeo game. Its just that it has to load the entire game into memory. Thats why MameDC sux so bad.