I've owned a copy of Poser for almost ... ten years now. Once you get the hang of it - it all starts to make sense. Like someone already mentioned, there is renderosity.com which has a large section of free items for poser .. and sometimes you'll get a helpful answer if you post in the forums. They also have a marketplace where you can buy some really neat things. But, I've got to warn you - not all of the merchants creations are there own - so watch out for scams.
DAZ3d.com is primarily a marketplace of high quality (and sometimes price) models - but they do offer a forum and some really high quality freebies. They've been a part of Poser way before anyone else.
A name you should look up is Dr. Geep
http://drgeep.com he has some really good tutorials.
Hope this helps.