There are many different interview techniques.
Here is a link to an article which includes some very good information on doing "qualitative" interviews.
Bates, C., Droste, C. Cuba, L., & Swingle, J. (2009, July 28). One-On-One Interviews: A Qualitative Assessment Approach. Assessment Notes. Retrieved 8/3/09 , from http://www.liberalarts.wabash.edu/storage/Assessment_Notes_One_on_One_Interviews_07.28.09.pdf
(permission to use from the Center of Inquiry in the Liberal Arts, Wabash College, http://www.liberalarts.wabash.edu/)
You might also find the following helpful:
Research Methods Knowledge Base: Interviews From the Web Center for Social Research. Trochim, William M. The Research Methods Knowledge Base, 2nd Edition. Internet WWW page, at URL: <http://www.socialresearchmethods.net/kb/>
Opdenakker, Raymond (2006, August). Advantages and Disadvantages of Four Interview Techniques in Qualitative Research [44 paragraphs]. Forum Qualitative Sozialforschung / Forum: Qualitative Social Research, 7(4), Art. 11, http://nbn-resolving.de/urn:nbn:de:0114-fqs0604118.
You might also find the following list of interviewer skills helpful:
Sample Interview Consent Form