There are two sorts of antenna "boosters", the external antenna with amplifier (proven, old-school electronics), and the little internal sticker-thing. I'm guessing you mean the sticker.
Do a Google for yourself, but what I've seen is no credible explanation for why they would work. I know lots of people (and TV Guide) claim they work and swear by them, and this leads to me speculate on how they operate - the stickers actually don't work on the phones, they just cause the owners to brag when they have good reception, and they get real quiet when they don't.
My samsung a950 is spotty at home and work, I love the features but reception is most important. I can either get the lg 8100 which works better(my mom has the fone) or try the antennae booster. My fone has an internal antennae. Please help