I use a converter box for mine. Either a msq700, msq100 or a Korg KMS-30 will do the trick (I have them all).... The conversion kits are nice, but I'm not fond of the midi timing for drums in the first place so I would not want to alter my 808 permanently for it. There is a easily removable kit available (forget the name), but there some issues with it.
for instance... can you send data to trigger individual voices with a box?
and with a middi fitted 808, do you loose control of the pattern editing when set to "out"? (#like you would using the original DIN)