I had a conversation with a guy from Getty the other day that said this is very much a real thing.  There are so many impressive images posted by photographers simply making cool images for the fun of it and not realizing their potential to earn big $.  I would flip out if someone from Getty wrote to recruit me!  Not likely to happen, especially since I almost never upload images on Flickr.

If you are truly serious about Wedding Photography then the information you receive on DWF for your annual fee will more than pay for itself.  I've been a member for around 5 years and I've found it to be an unending resource of great information from most of the industries leaders.  I'm not nearly as active there as I used to be as I belong to another wedding photographer forum that is more like DWF used to be with high end shooters but fewer people in general.  Because the DWF is so massive now it's a bit impersonal.  The discounts I receive because I'm a member have paid for my membership every year.  Especially the Prodpi discount.  One weddings print discount covers my cost

As for the free ones, you get what you pay for.  I would not recommend you jump into wedding photography head first.  It's one thing to shoot your friends and family for free.  It's another thing entirely to ask for thousands of dollars for your work.  The expectations are a bit higher and not being good with your strobes is not an acceptable explanation for why moments get missed. 

My best advice would be to find a reputable pro in your area and ask/beg/bribe him or her to let you carry their lights around for some weddings free of charge.  Maybe even 2nd shoot.  There is a heck of a lot more than taking pictures involved with wedding photography.

Mat Hayward
www.mathaywardphoto.com
www.mhwildlife.com
www.haywardphoto.blogspot.com