Hello,
I use their "Search" Feature at the project wonderful website to find blogs I like. You can also look at some of your favorite blogs and look for the link to "Bid on our project wonderful campaign" Below their current PW banners.
Hi -
There are two ways to find the PW ad boxes that you want to bid on.
One is to surf other blogs and if you see they have PW you can click on the text that says "your ad here" to get to their bidding page. I have two ad boxes on my blog that you can look at to see what I'm talking about. http://passitonplatesblog.blogspot.com/
The other way is to go to the PW website and do a search based on your preferred ad box size, how much traffic the site gets, where the traffic comes from, etc. There are a lot of online comix sites, but you can tailor your search by keyword, so if you want to advertise on sites within a specific topic you can search for that.
Some things I recommend doing, especially if you're starting out are:
1. Bid $0 or $.01 on as many boxes as you can, even if the current bid is a few cents. When the higher bids expire, your ad will be shown in the space until the bidding price goes up again.
2. Place ad boxes on your site. The money you earn by selling ad space will pay for your advertising on other sites so you can get onto higher traffic sites with no money out of pocket.
3. If you set your adboxes to auto-approve every ad, which will help you get more advertising faster, then check the bids on your adboxes frequently, or daily, for about a month. Like I said, there are a lot of comix artists out there, and I have learned (the hard way) that even though my adboxes are designated "Safe for Children" I was still getting graphic ads showing graphic renditions of T&A (ummm, that's breasts and bottoms). I immediately put up a notice on my profile explaining that ads not save for children would be canceled and the bidders would be banned from placing future bids on my ad boxes. Then I did just that.
I do a search on Project Wonderful using words like "craft, diy, etsy" and such. If it helps, I offer advertising on my blog :) http://pulpsushi.typepad.com