hi jeep man.
I dont know about anyone else but, when I have brought some harp's you sometimes get a bit of paper in the box with it, and if you actually look at it you will find that, there is a list on there which tells you all the cross keys and everything. I have one which I refer to all the time, as im an musically illiterate, it's a boon. the only thing I know is for blues you wack it up three keys, and the rest I use my bit of paper. if this bit of paper is of any help, please PM me and I will scan it and e-mail it to you. good luck,
pat.