My favorite is The Norton Anthology of World Masterpieces and from an essay called "The Pride of Lemuel Gulliver," by Samuel Holt Monk. That essay can be found in the Norton Critical Edition of Gulliver's Travels.

If you are an Enotes subscriber, the Gulliver's Travels side-bar has an entire section called "Essays and Criticism."  Here's a taste:

Gulliver’s Travels | Essays and Criticism

• The Historical and Cultural Background of Swift's Satire

  In the following essay, this author explores the historical and cultural background of Swift's satire and explains the differing interpretations of the ending of Gulliver's Travels.

• The Hairy Maid at the Harpsichord: Some Speculations on the Meaning of Gulliver's Travels

  This critic shows how Gulliver is treated as a monster during his journey, and argues that Gulliver accepts and even encourages this role in order to distinguish himself as an individual.

• The Satirist Satirized: Studies of the Great Misanthropes