[andrewas]

IIRC, that note is either a caesar cipher or a monophonic substitution. Whichever, theres a key for it on baldurdash.

To break it yourself, a caesar cipher is the alphabet moved along a certain number of spaces. So, in ceasar 1, a=b, b=c, c=d, ... ,y=z, z=a.

In a monophonic subsitution, the letters are randomised. So you have to count frequencies, the most common letter is probably e, the second most common is probably a and so on. I think its caesar though, because that note is really to short for proper frequency analysis.