There are many resources online for Tu B’Shvat. While no means a complete listing, here are some places to start finding articles, ideas, classes, activities and more. I suggest looking at a few sites and getting some overview of what they have.
JNF, a cosponsor for Jewish Earth Week, has an entire site dedicated to activities around the holiday:Tu BShvat Across America with JNF
Chabad.org has dozens of articles
Aish.com has many articles and materials