Here you have it in "one line":
Code:protected override void InitializeCulture() { var language = this.Request.QueryString["Language"]; if (!string.IsNullOrEmpty(language)) this.UICulture = language; }
You can put at the top of Guest.aspx inside the server script tag.
But I didn't include the dropdown. ASP.NET server controls aren't great here because the culture has to be changed so early in the page life-cycle. You could always use straight HTML select elements with some javascript.
How about just a couple of links somewhere on the page for your different languages? :
Code:
<a href="?Language=es-ES">Spanish</a>
<a href="?Language=en-US">English</a>
Or you can put the links on your feeder page. Or if you have users typing in URLs, you can use a different URL for each language (eg ensup.mycompany.com and desup.mycompany.com)?