管理多个客户端的Web服务视图/模板

I have a server-side web service that serves to multiple clients. Clients include web browsers, iPhone, BlackBerry, Android etc. My question is, I need to be able to generate dynamic content for views to these clients. Be it a full blown HTML template, an HTML snippet, JSON, XML, etc. Depending on the user-agent of the requesting client, a different "view" template gets generated and spat out by the web server. I have a server-side web service that serves to