The Frogs
http://classics.mit.edu/Aristophanes/frogs.html
An e-text of the play.
The Frogs
http://www.theatrehistory.com/ancient/bates029.html
A short history of the play, as well as related links, at TheatreHistory.com.
Aristophanes' Frogs Study Guide
https://www.ucl.ac.uk/classics/classical-play/archive/2009Frogs-studyinfo
A short essay, study questions, and bibliography from University College London.