I just found out all that stuff recently as well. The Wii has a 512 MB flash memory, so don´t worry about getting a memory card just yet. But just in case, the Wii will use an SD card as a memory card. It plugs in your tv just as the gamecube, with the input output cables. But if you have a new tv, you´ll need component cables.
Welcome to the forums by the way!
Have fun!