Heart to Heart International Ministries
Books and seminars on spiritual gifts.
http://www.heart2heart.org/

BuildingChurch.net: Gifted2Serve
An introduction to the spiritual gifts and their use. Online evaluation test.
http://buildingchurch.net/g2s.htm

Spiritual Gifts Test
Online Spiritual Gifts Test, 110 questions for 22 gifts.
http://www.kodachrome.org/spiritgift

Assess Yourself
Resources for self-assessment, identifying obstacles to spiritual growth, and discerning spiritual gifts.
http://www.assess-yourself.org

Team Ministry Spiritual Gifts Inventory
Developed by the Church Growth Institute, published by Ephesians Four Ministries.
http://www.churchgrowth.org/cgi-cg/gifts.cgi

Identifying and Deploying Your Spiritual Gifts
A basic overview of the theology of spiritual gifts, what they are, what the importance of them is, how to use them, and how to identify your spiritual gifts.
http://www.theseeker.org/gifts

Summit Manor Partners
Christian seminars and consulting, focusing on creativity and spiritual gifts--a professional organization dedicated to helping Christians implement their spiritual gifts in all areas of their Christian life
http://summitmanor.org

Gifts of the Spirit
A fairly thorough explanation of one particular understanding of spiritual gifts.
http://www.spirithome.com/gifts-sp.html