Loc111, I'd never flashed a phone before and was only one month into an 18-month contract with T-Mobile, but following the instructions on this thread it worked exactly as described (I confess, I had sweaty palms while it was happening though!)
If anything does go wrong (which it won't!) then I'm fairly sure people here will do their best to help you, so long as you're polite to them.
I'm in the UK and installed firmware version F480XXHF7
Samsung don't seem to do much of anything as regards updating the firmware on their phones - what your phone comes with is what you're stuck with unless you do something about it yourself.
I used to have a Sony-Ericsson, and they were very good at providing, publicising and helping with firmware updates, so it was a surprise to find everyone else didn't do this as well. Oh, and T-Mobile told me they didn't upgrade Samsung phones on their network either. They seemed to be fine about you doing it yourself (didn't void the guarantee or anything), but they didn't get involved in that kind of thing.
The new firmware definitely helps out with the camera problems - the camera's still not perfect, but it's actually worth having now.
Sadly, there's no improvement on the slow moving menus in the music browser.
Hope this helps,
StuPC