General/Overviews
Mature Skin (American Academy of Dermatology)
What Is Aging Skin? (American Academy of Dermatology)

Pictures/Diagrams
Slide Show: How Aging Affects Your Skin (Mayo Foundation for Medical Education and Research)

Research
FDA Approves New Product for Facial Wrinkles (Food and Drug Administration)
More Ways to Rejuvenate Your Face (American Academy of Dermatology)

Specific Conditions/Aspects
Aging Eyelids (American Society for Dermatologic Surgery)
Aging Skin FAQs (American Academy of Dermatology)
Collagen Creams: Do They Nourish the Skin? (Mayo Foundation for Medical Education and Research)
Liver Spots and Aging Hands (American Society for Dermatologic Surgery)
Smoking: How Does It Cause Wrinkles? (Mayo Foundation for Medical Education and Research)