Giant health-related websites are excellent resources, but don't discount the personal mental health blogs on this list. They are the best in the world.
Journaling is an excellent (and free) way to practice self-care. To get you started, here are 99 thought-provoking journal prompts for depression and anxiety.
Online therapy is great for clients who aren't comfortable meeting face-to-face. This is my review of Online-Therapy.com, which offers a unique, CBT-based approach.
Borderline Personality Disorder is marked by intense mood swings, problems with identity, difficulty tolerating stress, insecure relationships, and self-harm.