AdSenseAccelerator is one of the few products I've given a testimonial for. I actively use this product for my keyword research and can heartily recommend it to AdSense publishers who are looking for serious and accurate information about keyword pricing, especially bid gaps. You can read my previous review of AdSenseAccelerator (in three parts) for all the details: Part 1, Part 2, and Part 3.
I mention it here because they had closed their memberships for a while. They've added support for new members, so if you were waiting to get it now is the time to do it.
Eric Giguere is the contextual advertising expert who wrote Make Easy Money with Google and Uncommon AdSense. You can read this blog by mail if it's more convenient for you, just send a blank email to memwg-blog@aweber.com to subscribe.