My grandpa used to fix them like this:

Gut them, cut the head off (use a hatchet)
split in half (again with the hatchet)
Salt them down and put them in a big old crock (or washtub, or bucket) for 24 hours - with the salt, they make their own brine.
hang in the smokehouse and smoke them just like you would a ham.

End result - you can't tell the difference between smoked carp and smoked salmon.
That's the only way I've even eaten carp, and it was really good.