Thanks to the guys at Biblical Studies and Technological Tools for introducing me to the Open Scriptures Manuscript Comparator, a remarkable (and free!) online program which allows the interested user to instantaneously compare the readings of a number of critical editions of the Greek New Testament (including UBS 4, N-A 27, Westcott-Hort, Tischendorf, and the Textus Receptus). I've added it to the list of "Related Links" for future reference. Here's the Comparator's presentation of the opening verses of Luke 4:
The introduction to the program hints that New Testament manuscripts themselves will eventually be added to the list of texts available for comparison--which will dramatically increase its value to textual critics. An easy and intuitive way to compare and view disparate readings of Codex Sinaiticus, Codex Vaticanus, Codex Bezae, and the principal papyri, for example, would be absolutely groundbreaking. But in the meantime, I'm happy to make use of the existing features. Check it out!