I’ve found the “felt” font in the iphone (and ipod) notes app annoying, as I cannot change it to something more readable like arial.
After a bit of searching around, I found a few solutions.
Most revolve around adding a Chinese or Japanese keyboard, and then switching keyboards every time a new note is created.
An easier way is to delete the felt font completely.
For this, you will need to be able to delve into the iphones folder structure with something like ifile, or using ssh (ie this works best on a jailbroken iphone/ipod).
I have IOS4.01, so all I needed to do was delete (or preferably rename):
On other IOS versions, you might also need to delete:
The default Arial font was smaller than the felt font (which is what I want anyway).
If in doubt, just rename the font files back to their original name.