Subjective measurement techniques

• De Greef & IJsselsteijn's paper on the IPO Social Presence Questionnaire (IPO-SPQ)
• Frary's Hints for Designing Effective Questionnaires
• Lessiter et al.'s paper on the ITC Sense of Presence Inventory (SOPI)
• Lombard et al.'s page on Presence Measurement, including a pool of questionnaire items
• Kirakowski's Questionnaires in Usability Engineering - A List of Frequently Asked Questions (3rd Ed.)
• Schubert et al.'s Igroup Presence Questionnaire (IPQ)
• Witmer & Singer's paper on Measuring presence in Virtual Environments

Psychophysiological & behavioral measurement devices

• Eye movement equipment database
• Ascension Technology Co. (Motion tracking for e.g. postural responses)
• Astro-Med's Grass Telefactor (Neuro/psychophysiology)
• Biopac (Psychophysiology)
• Noldus Information Technology (Video observation of behavior)
• PsyLab (Psychophysiology)
• SensoMotoric Instruments (Eye tracking)
• Thought Technology Ltd. (Psychophysiology)