What you can do from your computer right now:

Take the time to give HGAC your comments. Let them know that you do not want urban neighborhoods sacrificed for communter traffic, specifically the proposed Northwest Corridor.
Volunteer and be added to a list of people willing to help when needed.
Email the name and contact information of your neighborhood home owner's association president so information can be distributed to your neighbors.
Keep checking in on the Upcoming Events page about meetings and news on this issue.
Join your neighborhood homeowner's association. Your money will help pay for some of the cost of fighting this battle.