Its only two speakers are Socrates and the titular character, who is returning from visiting Lysias.  
This work plays a key role in Derrida's Dissemination, particularly in his discussion of the pharmacy. This dialogue is set under a plane-tree, by the banks of the Ilissus.  Its only two speakers are Socrates and the titular character, who is returning from visiting Lysias.  Their discussion of Eros leads into Socrates' description of the two sometime-dueling desires, that for pleasure and that for the best.  This in turn leads to Socrates' monologue which includes the notable metaphor of the soul as a charioteer and horses. FTP, name this Platonic dialogue that ends with  the ostensible conclusion that writing is inferior to speech.
This work plays a key role in Derrida's Dissemination, particularly in his discussion of the pharmacy.
Phaedrus