I'm using Article Marketing Robot, very cost effective. You have to enter the captchas, but it automatically creates the account and confirms the email. There's over 2,000 directories in the database, I've created one account with 1,400 successful signups (don't use a free email). Supports the spin syntax. I'm not sure how much article directories accept the articles, but some show up to 100+ links pretty quickly.
Take a look at the following thread here at DP: http://forums.digitalpoint.com/showthread.php?t=26295
We are outsourcing our article submission work to outside services. It's quite cost effective. I think we can try the article subimtters later. Are they safe?