The number one top electric car forum in our opinion is the EV Discussion List. The list has been around for close to 20 years. These people can help answer just about any EV question you might have. There is a procedure to get logged on, so check that first. The easy way would be to use the subscription page.
Over 51,000 people have signed up on the GM Volt want list so far. If you are interested in the Volt, go to the Volt Forum. There are several other forums devoted to the Volt.
One of the more interesting areas of electric cars and vehicles is the use of ultracapacitor storage devices. At least one company claims to have a solution to the ultracapacitor as a practical storage device for electric cars. You can check some of the details at the Ultracapacitor Forum.
For electric bikes, there are a couple of forums to check out. First is the Pedelecs Forum and then there is the ebike Forum.
If you are interested in the popular Toyota Prius, we recommend you check out the Prius Forum. The members seem well informed and responsive to our questions at least.