First thing you should do is to install few addons to the Firefox browser which are as follows :
A. User Agent Switcher
B. Modify Headers
Now, we need to add a x-wap-profile HTTP Header. Most intelligent mobile Web sites look for this header to identify a mobile device. To my knowledge, only the iPhone doesn’t pass this HTTP Header. You can search around the Web to find UA Profile URLs (type “UAProf URL List” into a search engine).
Here’s the UA Profile URL for Nokia’s X6: