There is no specific section in the APA manual for citing lecture notes or slides.
However, there are some appropriate examples that can be modified from section 7.10 on Archival Documents and Collections (p.212-214). The bullet points listed at the beginning of this section state that the general format listed may be modified if there is more or less information given.
Rule #66 for Unpublished papers, lectures from an archive or personal collection would be a good format to use when citing lecture notes.
All information and page number references are based on the 6th edition of the Publication Manual of the American Psychological Association (2009/10).
Need a copy of the Publication Manual? Click here for details. See Also: APA Style Guide to Electronic References, Sixth Edition