The trademark sign can be found in the Symbols, Serif, and San-Serif fonts. You can use the 'character map' program in windows to browse through all the symbols available in different fonts.
In Word 2007/2010, click on the Insert tab/Symbol group. Click on the down arrow for the Symbol group (Omega icon) and with a Word file open, click on "TM."
To type the trademark sign you need to us the alt "key" and type a number sequence on the number keypad. So for the "™" symbol you hold Alt and hit 0153. Some custom fonts may not have this character so use a common one.