Changing web content based on browser type

[goliat4]

I'm writing a web application and I'd like to work out what type of browser/OS the request is coming from, and customise the returned content accordingly. So if someone visits the site from an iPhone/Android, they get a more streamlined experience, or if it's a desktop, they get the full version. I will pretty much take a completely different path, rather than try to mix the content together. What is the recommended approach for this in ASP.NET/IIS and PHP? Is there a single place I can catch incoming HTTP requests, make a decision, then redirect? Or is this usually done on a page by page case? Any gotchas I should look out for?Edit: A good point was made to make sure there is a link to the full version on the reduced version. That's a good point, but raises the problem that once the user make this choice, all future redirections now have to point to the full version. I'd really rather be doing all of this in one place.Cheers,Shane