Hello! Have you got a burning question about the archive that desperately needs answering? Do you have an exciting business proposition for us? Or do you just want to have a nice chat? Good, because we can help you with all three of those things! You can contact the archive administrator in one of three ways...
by email at info@lparchive.org by Private Message on SA to baldurk in our SA thread The LP Sandcastle
Unfortunately, if you want to get in contact with a specific LP author we can't really help you. If the LP author has a website (which should typically be linked to from the index of their LPs) you could try poking around there. If that doesn't bear fruit, the only way can suggest to get in contact with them is by sending them a message on the Something Awful forums.