Dynamically Changing Master Page

In MOSS we can change the Master Page dynamically based on conditions. This helps when we need to solve the problems like:

1. Chaning the Master page for a particular browser.
2. Changing the Master Page for a particular set of users.

The following code programmatically switch to the Pocket PC friendly master page when a "Windows CE" (pocket pc) browser is detected. In the following code, the master page, pocketpc.master, changes the layout, hides some of the content and references a CSS file with fonts and layout which are better suited for the smaller form factor of a pocket pc.

protected void Page PreInit(object sender, EventArgs e) {
if(Request.Browser.Browser.ToLower.Contains("windows ce")){
this.MasterPageFile = "~/pocketpc.master";
}
else {
this.MasterPageFile = "~/MasterPage.master";
}
}

For second problem we can find the users with the help of SPUser class and then assign the Master Page.