Tweet Attacks, along with PR Backlink Generator are extremely useful tools in the world of SEO. It is a bit pricey, but the results are absolutely amazing.
I created a website just 7 days ago, and it is already listed on the 2nd page of Google search when I was searching by the site's keywords. Before I started using these programs - I couldn't even find my site 10 pages back.
The site now logs over 250 visitors per day, and it's only been launched a week. I am getting an average of around 10-20 AdSense ad-clicks per day.
So yes, it is pricey. But is it worth it?
You bet your ass it is.