Per the suggestion of Robman46 (and that I want to level up passed caveman lawyer), here is a fan-freakin-tastic Lost theory (this is copied directly from my forum post on this, so i'm not doing any extra work):

Okay, I had this thought in my other thread 'guess the title of the season 3 finale'

someone (korupted) suggested that the title of the episode might be 'our mutual friend'-- the title to the book that desmond is gonna read before he dies, and it would bookend season 3 with charles dickens novels.

someone then brought up the producers referecne to the season 3 finale being a 'snake in the mailbox'-- and how the producers mentioned that it has something to do with the desmond/penny relationship

lastly, there is the 'spoiler' going around that the season 3 finale will be ben-centric, which makes complete sence

so, when i put all these things together, a huge idea came to my mind: what if penny was a 'mutual friend' to both desmond and ben. here are my reasons for saying this:

1) wouldn't this be a perfect explination for how penny knew to look for an electro-magnetic annomaly in her search for desmond? lets say that ben and penny are in communication-- penny giving ben information from the outside world in return for ben aiding her in her search for desmond. couldn't ben have helped her find the island, which brings me to my second thought

2) couldn't this explain why ben basically told locke to not press the button? isn't it possible that ben does not know how to get off of the island, but knows that it is protected by an electromagnetic barrier. not pushing the button would take down that barrier, even if only temporarily, allowing penny to come and find the island.

even if the whole thing on 'our mutual friend' isn't correct, i still think that this theory holds pretty well, but i would love to hear everybody's opinion.