Whatever you do DO NOT CONNECT an EXTERNAL ANTENNA to the CONNECTION POINT.
So far, everyone on this forum who has tried so with a Galaxy S has ended up with some permanent baseband (or whatever is responsible for the gsm/cdma part) corruption. What ended up happening was that the internal antenna would turn off. In some cases it meant that they could only call with the external antenna plugged in, and in other cases is meant that neither the external or internal antenna would work. (note: This has happened only on captivate and vibrant so far, so I am not sure what will happen on CDMA but.... Better safe than sorry right!?).
oh and sorry for the large font.... It catches your eye... ~_~