Well, you can e-mail Heidi... or you can use one of the following!
The Signing Time Dictionary is a great starting point. Rachel's explanations make it easy to remember the signs and the tape on her fingers help to see how the fingers are positioned.
Signing Savvy is a great site with an easy to understand dictionary as well as various learning tools. It is worth becoming a registered guest even if you are just starting out.
Life Print is another favorite resource. The variety of resources and detailed explanations are really great.
NHK手話 NHK Japanese Sign Language Dictionary