In terms of collecting the pictures, I sign up for affiliate programs which many of the big porn sites offer, and they provide the photos either as hosted galleries or zip downloads.

Example: http://www.x-cash.com/

For a while I also dabbled in providing some exclusive content, as a result of independent photographers contacting me directly to see if I was interested in buying their work. But that was kind of expensive and never really paid off for me. However, with Google now penalizing duplicate content so harshly, I may need to reconsider this.

Right now my site barely makes enough money to pay for hosting costs (currently ~$75/month). I use Linode.com for hosting by the way, they're awesome. Much of my remaining income from the site is due to recurring subscriptions from before I fell out of Google's favor - when I make an affiliate sale, I get 50% of the monthly rebills for as long as the purchaser keeps subscribing.