I read elsewhere, that even if it does have the FM radio inside it, that doesn't mean that it's usable because the phone may not be configured to use it. I don't care about the FM radio period so I don't remember what the guy said as I was just skimming.
It was a detailed explanation as to why it wouldn't work regardless, (something to do with parts of the phone not knowing how to use the FM transmitter regardless maybe...????) but it sounded plausible. If somebody searches through the forums, they may be able to find what the guy was saying.
That reminds me of my experience with purchasing a laptop with an Arrandale processor, which has on-chip graphics. When the chips and laptops first came out, most people were expecting switchable graphics on the new laptops when coupled with a discrete card. No dice: it required a hardware implementation by the laptop manufacturers beyond that, even though it was sitting there and available.
However, given that other Galaxy S devices do have FM radio including tuners, and since the Epic has that necessary hardware, I would suspect that FM on the Epic is just a software issue. I wouldn't expect Samsung to go out of their way to change their manufacturing process to disable the FM radio hardware (in a physical manner) when it would otherwise only be available to modders and hackers in the first place.
Edit: post #9
http://forum.xda-developers.com/showthread.php?p=7314420
"As far as the developers have been going about this, there have been a lot of signs that it's not existent. If you go about the threads, there are some posts about complete tear downs. Putting the two tear downs side by side, the FM chip hasn't been seen in the captivate where you would find in the galaxy-s (I believe the layout of the PCB is slightly different, but they couldn't find any chip that consisted of the proposed chip).
Also, if you try out the eclair i9000 rom, the FM app is included; however, the application states it fails to start the fm tuner."
Maybe they did change the manufacturing process on the US Galaxy S phones? I wouldn't have expected that. Do any of the US Galaxy S phones have FM working via modding/hacking?