If you haven’t already seen, we have a wealth of information on Lowrance/Eagle sonar, GPS, and mapping in the Outdoor Gear Forum. Here’s a link to the thread.
I’d like to thank Doc Samson for taking the time out of his schedule to answer questions and share his knowledge.
Thank you Doc! 
For anyone who is interested, Doc has produced a Lowrance Instructional DVD entitled “Your Lowrance: A complete basic instruction on the Lowrance system”. I have viewed the DVD myself and there is more information on there than we can possibly cover on the discussion boards.
Check out the Outdoor Gear Forum and feel free to ask any questions that are relevant to the topic. If you’re not sure if your question should go to Doc or to me, send it to me and I’ll either post it, answer it, or direct you to someone who can answer your question.