Just started reading a new book by Bryan Eisenberg & his brother Jeffrey entitled CALL TO ACTION, They have been involved in helping companies improve their conversion rates since 1998 and have had some impressive results.
The book is fasinating and full of very usefull tips and information on how to really improve your websites conversion rate, I will warn you now though they claim to have identified over 1100 diferent factors that can influence your sites conversion!
They have a whole sytem they reffer to as Pesuasion Architecture, which is designed to engage the user and move them through the site to the goal pages.
This is a fantastic book but not for the faint hearted as it's very hard core and should only be read by those of you looking to really make your websites fly.
The book is published by Wizard Academy Press ISBN 1-932226-39-7