Whether or not there is an FM receiver is a non-issue for me personally.

However, since there allegedly is one, how difficult/likely would it be to implement time shifting capability? I do occasionally listen to sporting events and the ability to pause a live event could be quite a compelling feature?

Is it even doable with this hardware?

My guess is someone will write something pretty quick if the driver is functional. It's too attractive too ignore.

An app that routed a live FM signal through a buffer to allow DVR-like control would be interesting. Maybe even a speech-to-text conversion addon for talk radio or feed of tweets about what you're listening to.

I've always liked and used the FM radio in my Nokias in the past. I'm glad to see they included it on the N900.

Not having the FM receiver on the N900 wouldn't have been a deal breaker for me, but it would have been missed. I use the FM tuner on my N800 frequently.

So what happens if you tune the FM receiver to the same station your broadcasting your sound over on the FM transmitter. This can't be a good thing - seems like the feedback / noise would cause something to overload / break.

I must of been typing while you posted. IMO setting up a DVR style program wouldn't be that bad. My guess would be to write the audio from the FM radio to an audio file (via a hidden command line application) and an app with a GUI to control said app and play saved ones. Again, possibly not that bad. The question is can you keep the CPU load down enough not to burn too much of the battery.

This is the first time I read about time-shifting with FM radio, but the idea sounds interesting.

Worst case they could disable FM transmitting while the FM receiver is in use. Although I can see a situation where it would be useful to have both enabled at the same time - for GPS turn by turn while listening to the radio.

Perhaps the receiver driver can lookup the frequency you are transmitting at and prevent tuning to that frequency? Surely there is some functionality already in there to prevent feedback, but what?

That said, what are they using for the antenna? If they both use a headset/headphones for the antenna wouldn't that be a "bit dodgy" having both at the same time?

The big question for me is if it has a built in antenna. My p1i's FM radio is nice, but you have to have the headset plugged in as it also acts as the antenna.

If the N900 does not require anything additional to be plugged in for reception, that will be super nice.

A built-in antenna wouldn't be sufficient for reception (see the N800). You have to connect headphones or at least a compatible cable.
I'm not a FM technician but I think a FM antenna needs to be a certain length.

I agree. It would need a "telescoping" type that would pull out from the device, perhaps a meter in length when extended.

Hum, a telescopic stylus. Think of it.