Most guitarists just don't want to do it. That's alright...there's tablature, but this style of notating pitches is exclusive for just the string instrument for which it's written. Here's an example from a piece for Vihuella.
 
 
 
Here's the question then: how does the string player, who reads and writes their ideas in tablature, communicate their original idea to another musician who plays an instrument like piano or tenor sax or whatever? Already it's starting to get way stupid.
 
This to me is the single most motivating factor. The need to communicate musical thoughts and ideas. Notation provides musicians with an essential means of communicating their language. So here we go, first we'll talk about where the notes are on the staff...
 

 
The lines of the staff give us, from lowest to highest, E G B D F. I remember this by creating a memorable saying like this Ernie Gave Bert Dead Fish. The spaces between the lines just give us the word 'FACE'. The cool thing is that the order of notes on the staff are alphabetical as you go from line to space and space to line. Each string is alphabetical too, you just have to contend with sharps and flats.
 
So here we are...knowing where the notes are on the staff, but this pretty much means nothing unless we can put them in their places on the fingerboard de su gitmo. If we list the notes on the A string from the open string up through the 12th fret you'll know the musical alphabet, which you can then apply to each of the other strings. The open string is the A, the 1st fret is A#, the 2nd is B, the 3rd is C, and so on.
 
A A# B C C# D D# E F F# G G# A 
 
So now let's apply this to the 6th string (E).  All we're going to do is take the musical alphabet and start and end on the note E. Here's what it'll look like...
 
E F F# G G# A A# B C C# D D# E 
 
And it'll work this way for each string! So now we have to take our new found knowledge of the fingerboard and the staff and tie things together. In music notated for the guitar, no matter the style, you'll be given more than just the note on the staff. Here's an example...
 

 
You can probably figure on your own that this note is B, middle line of the staff. That's great for piano because there's only one way to produce the note, by pressing a key. In guitar notation, it will look like this...
 

 
The circled 3 is the string assignment, in other words telling you what string to find the note on, and the non-circled number 2 is the finger that the writer/composer suggests you use. My point is a guitarist can play this B on the middle line of the staff in numerous locations of the fingerboard. There's an example of this further down but let's get used to finger and string numbers first. Your left hand fingerings are like this:
 
1 Index
2 Middle
3 Ring
4 Pinky
 
and the strings are labeled this way...
 
E 1
B 2
G 3
D 4
A 5
E 6 
 
Here's another example... 
 

 
In this example, the first B has an 'o' next to it, Oui? That o signifies that the note is played as an open string. The second B has a circled 4 which means to play it on the 4th string [d string] with the 4th finger. As mentioned before, you can more often that not perform the same note on different strings.
 
[please pardon the lack of video accompaniment, I was given avian flu by my grandmother's Jamaican nurse. To her credit, I don't think she was aware of her carrier status.]