And thusly were the wise words spake by Zane H. Healy
 I am interested in the C-64 and Apple ][ computers, and in keeping them
 running, I had neither when they were current, and only got to touch one a
 couple times back then.  I'm actually looking at the devices that let you
 use MMC cards with interest (I know they exist for the C-64, and assume they
 exist for the Apple ][).  The same goes for the PDP-11 to a certain extent,
 however, I've moved to SCSI drives on both my Unibus system, and my Q-Bus
 systems.  In the case of the PDP-11's though I'm more inclined to use an
 emulator, and have been leaning towards prefering the emulator for several
 years.
  
Zane,
        There is the IDE64 which allows you to hookup IDE drive,
CD/DVD-ROMS and Compact Flash cards.  Plus the creator is working
on an ethernet adapter that would attach to it.  Right now the IDE64
board is in its fourth revision.
        There is also the Retro Replay cartridge (a program
freezer) which has an addon called the RR-Net that gives you a
10Mbps (yes I know the C64 can't move that much data!) ;) ethernet port.
This is supported by the Contiki OS which is set to move to V2.0.
Cheers,
Bryan