I found a bunch of links for information about infinitives.
Infinitive - Wikipedia, the free encyclopedia
Verbals: Gerunds, Participles, and Infinitives (halfway down the page)
Infinitive (simple explanation)
English Study Quiz - Gerund or Infinitive (quiz on distinguishing between gerunds and infinitives)
Identifying Infinitives (what part of speech the infinitive is in)
Student or Learner