IIS rewrite rule for adding country code in url

Question

I have one question regarding url rewrite. suppose i want to add country code in my all url say www.mysite.com/gb/home.aspx or www.mysite.com/de/home.aspx but there will be no folder  called gb or de rather when the above kind of url will be issued then i need to internally send the request to my root home.aspx file and country code will be passed as query string. how can i achieve this with IIS rewrite rule. i guess we need to handle it with iis rewrite rule but i do not know how iis rewrite rule would look like for this scenario. if anyone know then can share the code for iis rewrite rule which i need to write in web.config file. thanks