I'm still torn. Can you get a wheel on PS3? Do you need one? And are the graphics better on high end PC or PS3?
Also can you edit drivers and teams? Otherwise in 4 races time everything will be out-of-date.
In terms of wheels, you have two roads to go down, cheap or expensive. Logitech (which is really the only make you should consider) do the DFGT, which is ~?70, I use this, it's a good wheel but the pedals aren't the best. However, if you want good pedals you're looking at G25 or G27, both very good wheels, but come at a price. G25s are about ?160, G27s are ?230 and more.
All three will work on PC or PS3. As for whether you need a wheel, no, but it does make the race gaming experience so much better, and the DFGT is more than good enough for that as a "cheap" wheel.
Graphics are definitely better on the PC, but they have said they're looking in to improving graphics in future patches (yes, they used the plural). I think it's obvious this part of the game had to take a back seat so they could get it out during the season (FIA won't let it be released outside of F1 calendar). Also, because 360 and PC use different graphics languages to PS3, they both have an advantage over it. Then again, I'm happy enough with the PS3 graphics.
I've not seen anything which shows you can edit drivers or teams. This is an FIA thing rather than a Codies thing, protecting IP, etc.
Edit: Also worth saying in the "Shall I buy a wheel" question, is of other racing games on the horizon. DIRT3, rallying/off-roaders, DIRT2 was very enjoyable, particularly on-line with mates. The big one is GT5, which is out in a month. rFactor on the PC is also good, as it's so moddable you can pretty much do anything you want with it. There are historic mods (GT, F1, Tourers) more circuits than you could want, etc. rFactor 2 is out soon as well.