Yes Costello, I know homebrew can only use the first one. It's a slot 2, M3 MicroSD lite dshobro.ds.gba.
My config
PC: Windows XP SP2 with Firewall disabled, port UDP 9000 is open. IE7
DS Lite with M3 Lite (slot2)
WRT54G with DD-WRT 23sp3 and my WFC works fine with MKDS and other wifi games...