Ok, so this was actually live last week, but hey. James Senior blogged last week about Live ID Customisation last week, and also commented this week that LiveWIM have changed their Live ID Sign In page. This is actually a very simple process, and is all described in the MSDN documentation.
You can only do this if you are using the Windows Live ID Web Authentication, which is what we use. I’ll assume that you have your application already set up and configured on http://msm.live.com, so to add this new functionality, head on to https://msm.live.com/app/ManageCobranding.aspx and sign in with the WLID that manages your application. Select the application, this will then give you the option to upload your xml file that has all your configuration changes. If you don’t have an xml file already, then don’t worry as you have the option to download a template:
To edit your xml file, I recommend using XML Notepad as it made things very easy for seeing which element was what:
Save your xml file, upload it using msm.live.com and you’re off and away. I found that changes (especially logo changes) didn’t always take effect immediately, so some patience might have to be employed.