I use Weather Infinity on my Palm based devices as it is a very good and very cheap weather application, certainly better than for example the likes of HandyWeather where they try and shaft you up the derriere each year via their ludicrous annual subscription model.
I see that the developers now make a version for the iPhone and it is very cheap too. If it is as good as the palm version it will be worth checking out.
On my E71 I am continuing to use Mobile Weather as it is free, the two alternatives are HandyWeather and ForecaWeather both of which are $20 or more and charge an annual subscription. I don't know what it is with s60, I have come across quite a few apps that have annual subs too, including Resco Neeews for some reason…they don't charge it on the Palm platform though. I wonder why?