I want to make a fire truck cake but I'm not sure how. Can anyone help me? I did a search but didn't come up with what I was looking for.

Wilton cake pan fire truck cake:

http://www.wilton.com/idea/Fire-Truck-Cake

3D fire truck cake help thread:

http://www.cakecentral.com/cake-decorating-ftopict-647265-.html

How to make a simple 3D fire truck video tutorial:

http://tinyurl.com/n8n28v

Fire truck cakes from the photo galleries:

http://www.cakecentral.com/modules.php?name=gallery&meta=search&type=full&search=fire+truck&album=55&search_user=

HTH

You could also look at tierfuldesigns.com
Michelle has quite a few trucks and cars in her 'carved and 3D' section.
HTH