if you are just snorking, hol chan reserve has quite a variety of fish, not pelagics though. the blue hole usually has some sharks in it, 6-8 foot range. best bet are the walls off of lighthouse reef, most start at 30', some go down thousands. the elbow is especially cool.
local around san pedro i like most of them, just explore, describe to wichever shop you pick what you want to see and they are generally very accommadating.
As for conch, the season starts inthe fall, don't know the availability right now (anyone help?)
[This message has been edited by fred (edited 05-16-2000).]