My ideas are only a drop in the bucket of Web 2.0 resources for educators of gifted and talented students.
The following links can start you on a journey of infinite ideas:

GT Websites:
The Association for the Gifted
Broken Arrow EL Center (Shawnee Mission School District, Kansas)
Center for Gifted Education at William & Mary
Colorado Association for Gifted and Talented
A Different Place (Nancy Bosch)
Education Consulting Service (Susan Winebrenner)
GT CyberSource (Davidson Institute)
Gifted Development Center (Linda Silverman)
Hoagies' Gifted Education Page
National Association for Gifted Children
GT Blogs & Podcasts, including student work:
Creating Lifelong Learners (Mathew Needleman)
Gifted Exchange (Laura Vanderkam)
Gifted Kids Network Student Blogs (Boulder, CO)
Gifted and Talented in the 21st Century (Michele Eckstein)
Gifted Kids Network (Michelle Eckstein)Ginger Snapz (Ginger Lewman)
My Learning Train (Kathy Ellis)
Unwrapping the Gifted (Tamara Fisher, Teacher Magaine)

Social Bookmarking:
GT Bookmarks on Diigo
CAGT Del.icio.us Bookmarks

Social Networks:
Gifted Education 2.0
Enrichment 2.0
Classroom 2.0

Wikis:
Flat Classroom Project
Eduwiki.us
SUHSD Differentiation
GT Resources Wiki