Can't get my copy to post - BUT I found the original post by Grau Geist!
It wasn't where I thought!
Go to Aircraft Camouflage and Markings, in the TECHNICAL section.
There's a thread there entitled 'P51D', by ZMSD. Dave's (Grau Geist) post is #9, and has the attachment for the fonts on a Zip file. Just download it, and you're ready to go.
You may need to re-size the chosen font, to obtain the scale size you want, hence my suggestion of a test print on paper first. Once satisfied, just feed the inkjet decal paper as normal, and print the required decal set.
Allow this to dry for 30 minutes or so after coming out of the printer, just to be on the safe side, then spray with clear varnish. As I mentioned before, Johnson's Future will be ok for this, preferably two coats, sprayed, allowing the first coat to dry thoroughly before spraying the second coat. If you don't have an airbrush, an aerosol can of acrylic clear varnish will work just as well. Leave the varnish coat to thoroughly dry, preferably for 3 hours or more, to ensure it has toatlly hardened. Then, cut and use just as you would 'normal' waterslide decals.
I'm not sure how these decals will perform with decal solutions, such as Micro Sol or Micro Set, as I have only ever used one type of clear decal paper - those from different manufacturers may perform or react differently. Best bet is to test on a spare decal, on something unimportant.
Hope this helps.
Terry.