Kaplan DAT study guide.
Exam Krackers 1001 (for GC, OChem and Bio)
TopScore CD (scholarware.com)
Kaplan Course Flash-cards.
GRE study guides (for the QR section)
Barron's DAT study guide (for the PAT section).
Kaplan Guide with CD rom
Topscore www.gre.org for math and science review sections
schaum's outlines (pretty detailed)
barrons for PAT
college textbooks