I understand how to read standard notation, but was attempting to practice this and hit upon a problem transcribing a song the other day. The problem is that I'm not sure how to notate two notes of the same pitch ringing simultaneously (although they do not start or finish sounding at the same time). The song was Heartbeats by José González, incase my description was not clear enough (also it shows how necessary it is for this to be notated in the music as it's important to the quality of the song).

I'd appreciate some help if anyone knows how this is done? It's obviously not an issue that occurs on many instruments, most not being capable of playing the same pitch in multiple places at once, so asking musician friends of mine for help produced confusion (and amusingly outrage at the apparent audacity of the guitar for producing such a question... but there you go).
in choral notation, if two voices are singing the same note, it has a stem going up and down, not sure if that applies
Quote by CHOCOmoney
in choral notation, if two voices are singing the same note, it has a stem going up and down, not sure if that applies

You can do this or put the two heads of the note on either side of the stem, not sure how that would work with the differing length issue though
Thanks for the input, but to notate them on the same stem, or both stems on the same head, I would need to tie them to other notes to distinguish the differences in duration and when they come in, which would seem very confusing to anyone reading it.
I'm trying to imagine how it would look in my head. Use up and down stems definitely, and make sure you put rests in for whenever one of the parts isn't playing. For instance, if the first part sounds on the first beat lasting a minim and the second part sounds on the second beat lasting a crotchet, you'd have to put a crotchet rest underneath the first note, otherwise it would look like the second note sounds on the third beat (when the first note ends).

So long as it's not ambiguous, it should be alright. Whether it will be intuitively readable is another matter. It's not something I've come across before as all my sheet music is for piano.
Separating into parts is probably the only way to make it correct I guess. But if you know the song, or youtube it, it's all part of the melody, it's just that the notes are held afterwards. But it should flow as a melody I just can't see a way of notating it to still resemble one. But it's nice to know i'm not just plain missing something :-)