I have tried to contact the creator of these letters to no avail. As best as I can tell they have not been involved with the project for a long time so it may be a moot point.
Given that, I would really like it if someone can give me some pointers of other very similar projects or guidance on where to start.
Here is something that is somewhat similar. AETUTS+ is a great place for After Effects tutorials: http://ae.tutsplus.com/
From what I saw you can download all 26 fire letters for 30.00 from the vendor site: http://www.thirdmenson.com/3dstore/index.php/AE-Projects/Realistic-Tex t-on-Fire/shop.flypage_ae.html
I hope this helps! : )