If you're just looking for an extra search for part# BTR6300B on amazon or wherever you like to shop. It's a common battery that is used in several other HTC phones.
It depends which battery you're talking about. HTC makes 2 batteries for the incredible. The 1300 mAh battery is the same battery that the trophy uses. The 1500 mAh battery is slightly thicker and will not allow you to replace the battery door on the trophy. Just make sure it's the part number that I listed above and it will fit.
vzw.com has the batteries, and you can call up and order one. If youre going ot buy from a store, try the corporate stores first. Resellers buy their own inventory so they arent necessarily going to have it.