Have a few questions.

I have been getting sales from people joining my newsletter since we offer a OTO at almost 50% discount. I'm seeking tried and true ways to build my list. I now have 605 using aweber. I'm going to offer a free pc repair ebook download if they subscribe. I'll change my site, and 2 other sites, to show this.

Which is the best way to build my list. I see three co-registration sites, AdvertisingKnowHow.com, ListCrew.com, and NitroListBuilder.com that I can use. Have you had any experience with these? And what other proven list building steps should I take? I'm also trying Article submissions.