To learn the program itself I highly recommend the video by 3-axis. Joe Grover, who is no lightweight when it comes to all things 3D, goes through all the Poser 5 rooms in detail. I'm sure you will find his straight forward friendly approach easy to follow.

Another publication you may want to consider is Secrets of Figure Creation with Poser by B L Render. Although I have not seen this personally I understand that it is getting good reviews from those that have purchased it.

For more information on how to create content for Poser may I also point you towards a tutorial that I have published. Details may be found at http://www.philc.net/tutorialsIndex.htm together with a number of other online tutorials that I hope you will find of benefit.