Note: These titles will work in WMM 2.1 (XP) and WMM 6.0 (Vista/Win7). I've provided XML for both versions in the installers.
There are two installers depending on whether you are running on a 32-bit or 64-bit version of Windows. The installer will put the necessary files into, C:\Program Files\Movie Maker\Shared.
Go to 'Tools' > 'Titles and Credits' > 'Title on the selected clip'.
Type your text in the first box.
Click on 'change the title animation'.
Under your list of one line titles, find the new animation in the desired color:
As with other titles, you can change the font and other styling attributes. Finally, click 'Done'.
Adjust the title duration by shrinking/stretching the rectangle on the Title Overlay track.