an adwords campaign would do one of those sites good however it depends on whether you have the budget or not.
If you spend money to advertise GPT sites just to get referrals, that wouldn't be smart. Especially when you could use adwords or something to advertise something that pays alot more. Say $20 bucks. To advertise GPT sites for free. You need to do it like everyone else - Forums, your blog, flyers, socialbookmark etc. Here's a few tips to get more referrals for your GPT sites
I would say to advertise on PTC sites. The people using them are looking to make money so would be more likely to join other programs