Steps involved in setting up a website for mobile users ?? Does it depend on the hosting provider OR the way we write code ??

Well, the code you write must be compatible with the hosting environment. For example, if you're writing a mobile site using C#/.net, you're not going to get very far hosting it on a Linux Server :)

Other than that, a mobile site is whatever you create it to be! Typically, these are stripped down versions of a more complete site, or in the event you're creating a site meant only for mobile use, it's a site designed to be fast and relatively simple, in terms of interface design.

Dumb question but can they be written in any web language?