LimeSurvey is an Open Source Online Survey Tool, which was known until May 2007 as PHPSurveyor.
LimeSurvey basically contains everything you need for doing nearly every survey with grace.
LimeSurvey currently offers:
* Unlimited number of surveys at the same time
* Creation of a printable survey version
* Unlimited number of question groups in a survey
* Unlimited numbers of questions in a group/survey
* 20 different question types with more to come
* Ability to set conditions for questions depending on earlier answers (branching the survey)
* Re-usable editable answer sets
* Ready-made importable questions
* Assessment surveys
* Unlimited number of participants to a survey
* Anonymous or open surveys as well as closed surveys
* Optional public registration for surveys
* Sending of invitations, reminders and tokens by email
* Option for participants to buffer answers to continue survey at a later time
* Cookie or session based surveys
