Transposition is just maths - in fact, not even that: if you can count, you can transpose. All you need is a picture of one octave of a piano keyboard (get someone to write the letter names on if you don't know which note is which). Start on the first note of the tune you want to transpose. Find the note you want to transpose that to. Work out how many notes (white and black) you have to count to get from your original key to the one you're transposing to. Then just count the same number up or down (but always in the same direction - if you first counted downwards, then keep counting down) from all the subsequent notes or chords.

Hope that makes sense - it's far easier to show someone than explain it on a screen.

Jude