Hi there,
Unfortunatly under the rule of Steve jobs, apple have forced you to use their hardware to create their software! You must use an apple computer running OS 10.5 or later. to apply to be an apple developer (to sell your software you must sell it through apple) it costs about $99 for a personal licence, or about $350 for a commercial one I think.
(Or if you are smart you could get in there when it was a beta and get a free one!)
The native language used on the apples is whatever one that they include in xcode, I'm not 100% sure on what it is, but I know that the iPhone supports coco too.
There is really only one (less than legal... thus I do not recommend!) option for not buying a Mac for developing these and that is to create a hackintosh by over-riding some BIOS settings to force your PC to think it is a MAC and use hooky OS to create the computer, but this is not legal, not reliable and 90% I think it is a waste of your time.
If you are doing this through a company I would suggest buying a Mac Mini for £399 and just paying it off in £15 monthly payments if money is an issue.
Once you become an apple developer, there are great videos and examples in the developer center on apple.com to help you get started.
Mark